Salmon with bergamot oil, roasted kumquats and fennel

Sometimes, you just have a bit of a brainwave in the kitchen. A sudden spark of inspiration, filling you thrillingly with the utmost conviction that yes, these two ingredients are just made for each other, or that wow, that would be the perfect cooking method for this particular thing, or that yes, it is completely a good idea to alter such and such a recipe in a certain way to make something new and wonderful. These are wonderful little moments of insight, familiar no doubt to anyone who is lucky enough to indulge in the creative process as a hobby or even as a career path. I only wish I had as many moments of revelation during my PhD work as I do during my kitchen hours.

Perhaps this is okay, though - convenient, even. Nature, observing that I am spending my working hours grappling with ridiculously abstract concepts, horrifically complex academic treatises and a general nebulous mass of incoherent ideas, kindly decides to make everything come together and make sense in at least one area of my life. And let's be honest, if there's one time when you want everything to make sense, it's when eating is involved. Far more important than academic matters.

A bowl of kumquats had been providing me with a source of anxiety for a couple of weeks.

(This, in my world, is a totally normal sentence.)

Seriously, though. I was wracking my brains to decide what to do with them. Although I could have made this delightful kumquat and vanilla cheesecake again, I figured I should branch out a bit. I thought about an upside-down cake, but it never materialised. I wanted to use them in a savoury dish, given my penchant for fruit in savoury food, but the ideas weren't really flowing.

While I pondered, there they sat in their little punnet, looking totally inconspicuous in an orange, bulbous sort of way, until I realized that a couple at the bottom of the pile had turned blue and furry, and were thus polluting and infecting the rest with their mouldy pestilence.

Thus began a battle against time, to save the kumquats before that tragic disease of the blue furry coat spread throughout their ranks and decimated the lot.

Gosh, it was stressful.

Kumquats aren't the most common of ingredients. I reckon many of you won't ever have tried them. They look like little elongated oranges, with a firm shiny skin. Their flavour is intensely refreshing, quite sharp and sour but with a really strong citrus hit. They are a powerful little ingredient, and need something quite strong (or sweet/creamy, hence the cheesecake) to balance them out.

I'd been pondering various uses: in salads, as a compote alongside meat (they're quite good with venison), as a compote on top of porridge...until one day, I don't even remember why or how, I suddenly had the brainwave to roast them with some wedges of fennel and serve them with fish.

I can't really tell you why I thought this would be a good idea. I guess it started because I love the combination of fennel and fish. I usually just shave it wafer-thin and serve it as a salad, but I thought its aniseedy crunchiness would be wonderful roasted into soft, melting, sugary tenderness in the oven. I thought roasting the kumquats would concentrate their intense citrus flavour and also soften them a little, as they're quite hard and crunchy when raw. I figured the whole lot - sweet, fresh, crunchy, sour - would pair very well with the rich oiliness of cooked salmon.

I could have complicated this recipe quite a lot. Added some wedges of cooked beetroot, maybe. Some grains or pulses to bulk it out a bit. More herbs. Some toasted pine nuts for crunch. Wilted spinach for greenery. All of these would be excellent additions, I'm sure, but for once I wanted to keep it simple. Just salmon, fennel, kumquats, and mint. Fresh mint works very well with fennel and with citrus, and here it is perfect, giving a lovely freshness to the roasted vegetable and fruit medley.

I sprinkled the kumquats and fennel with a little sugar and drizzled them with oil before roasted them for half an hour or so. Their edges scorch and become burnished and caramelised, while they soften and become more concentrated in flavour, much sweeter and almost melting in texture. Tossed with salt, pepper and fresh mint, they are absolutely delicious.

Finally, a drizzle of some fabulous bergamot-infused olive oil from this wonderful range of infused olive oils that I've mentioned before (see this chocolate and mandarin olive oil cake). If you've never tried bergamot before (apart from maybe in Earl Grey tea), it's fantastic - incredibly zesty and fresh, rather like a cross between a lime, lemon and grapefruit. This oil really packs a punch - it was the first time I'd used it, and I couldn't believe the amount of flavour it brought to the salad, combining really well with the rich fish and the zesty kumquats. If you don't have bergamot oil, though, you could just add a drizzle of olive oil and a squeeze of lime.

This is an incredibly simple recipe, but it is unusual and delicious. The roasted fennel and kumquats with the mint and bergamot oil would make a fabulous side dish to accompany most things: chicken, fish (particularly trout, mackerel and salmon), pork and grilled halloumi cheese would all work wonderfully with it. As it's quite sweet, it works very well with rich things that need a little taming, like oily fish or cheese. It's a real riot of fresh, zingy flavours, yet warm and comforting at the same time from the soft caramelised fennel. I'm pretty proud of this ingredient combination, as it's not one I've ever seen before but it just works so well.

A perfect way to use up an anxiety-inducing bowl of maturing kumquats.

Salmon with roasted kumquats and fennel (serves 2):

• 1 large bulb of fennel, sliced into wedges
• 12 kumquats, halved
• Olive oil
• Salt and pepper
• 1 tsp brown sugar
• A few sprigs of fresh mint, leaves finely chopped
• 2 fillets ready-cooked salmon
• 2 tbsp bergamot-infused olive oil (optional - you could also use lemon-infused oil, or just olive oil with a squeeze of lemon juice)

Pre-heat the oven to 180C. Place the fennel and kumquats in a baking dish and drizzle over a little olive oil. Scatter with salt, pepper and sprinkle with the sugar. Toss together. Roast for around 30 minutes, until starting to scorch and caramelise, and the fennel is tender.

Divide the fennel and kumquats between two plates. Sprinkle with the mint and flake over the pieces of salmon. Finally, drizzle with the bergamot oil and serve.

Kumquat, vanilla and ginger cheesecake

I've decided to further investigate the intriguing kumquat. I have eaten these little citrus beauties three times: first at Gordon Ramsay's York & Albany restaurant; next, I tried them in a sharp compote with venison, and last week I decided to explore their dessert potential. I find them curiously exciting: I think it's because you wouldn't think, from looking at their dimpled, waxy skins, that you could put one in your mouth whole and enjoy it. Yet you can: they have an astringent edge that ideally requires the mellowing effect of dairy, but they are certainly not unpleasant raw and unadulterated. I love finding a new ingredient and thinking of interesting and tasty ways to use it. Seeing as the kumquat is part of the citrus family, I started thinking about other flavours that go well with oranges and lemons. I came up with ginger, and also remembered the blood orange cheesecake I made a while ago. I decided that the tartness of the kumquats would work very well folded into a crumbly, sweet, creamy cheesecake.

I debated over what type of cheesecake to make: both the unbaked, gelatine-set version and the baked, crumbly, thickly creamy version have their merits. I think either would work with the kumquats, but because they are so sour, I decided they needed a stronger cheesecake mixture with more texture to stand up to them, so the baked version won. Plus I just love making baked cheesecakes: it's immensely satisfying to spoon a bowlful of loose, creamy cheese and eggs into a tin and watch it emerge a little while later with a golden hue on top, cracked in places and starting to turn firm at the edges, but still with a little gelatinous wobble in the centre.

First, I made a kumquat compote. This was nothing more than a little water and sugar boiled together until syrupy, to which I added some quartered kumquats and cooked with a lid on until they had softened. I then stirred in rather a lot of ground ginger. This is incredibly delicious as it is: the skins of the kumquats become soft and slippery and taste rather like the thick zest you find in rustic, homemade marmalade. I ate rather a lot of it for testing purposes. The ginger gives quite a kick to it, which, combined with the intense sweetness, is wonderful. It's immensely refreshing, like the fruit itself: it has the edible tartness of grapefruit, and the perfume of orange.

Next, I made a basic cheesecake mixture: ricotta, creme fraiche, eggs, sugar, a little honey. I also added rather a lot of vanilla extract: I've become a bit obsessed with it lately, and as it somehow makes everything taste sweeter, I thought it would help heighten the contrast between the tart fruit and the sweet cheesecake. I sprinkled some crumbled ginger biscuits over the bottom of a cake tin for the base, and then swirled some of the kumquat compote through the cake mixture. I poured it over the base, and put it in the oven for about 50 minutes. It took longer to cook than I'd expected, probably because the mixture came quite high up in the tin. I left it a little bit wobbly in the middle; that way you get a delicious creamy centre and a thicker, crumbly exterior.

When the cake had cooled, I spooned the rest of the kumquats on top. I was going to arrange them into some kind of Michelin-starred precision, but then realised that they looked pleasingly rustic just piled on top. A sprig of mint, and it was finished. The contrasting colours are just beautiful: dark biscuit, creamy golden cheesecake, and the luscious orange of the citrus fruit on top.

It tastes wonderful. I was really pleased with this, especially because I made it up in my head and it worked out as well as I could have hoped. The combination of creamy cheesecake with firm, tart-sweet fruit is delicious; the little slivers of kumquat hidden inside the cake are a lovely surprise in every mouthful. The ginger in the compote and in the biscuit base is also excellent with the sweet creaminess of the cake. I'm very happy with this.

Kumquat cheesecake (serves 4-6):

• Kumquats (I didn't weigh them, but about two large handfuls should be enough - or you can use more and make extra compote to eat with ice cream or porridge)
• 100ml water
• 60g sugar
• 15 ginger nut biscuits
• 2 tsp ground ginger
• 250g ricotta cheese
• 150ml creme fraiche
• 90g caster sugar
• 2 large eggs
• 1 tbsp honey
• 1-2 tsp vanilla extract

Pre-heat the oven to 170C. Grease and line an 18cm springform cake tin (you can use a 20cm tin - if so reduce the cooking time by about 5-10 minutes).

Place the sugar and water in a small pan and heat until boiling. Quarter the kumquats lengthways, remove the stones, and place in the syrup. Cover with a lid and simmer until the fruit has softened. You want there to still be some liquid remaining in the pan - add a little more water if it has dried up; conversely, if it is too runny, take off the lid and simmer for a bit. Add the ground ginger and leave to cool. Taste it - you might want a little more sugar or ginger.

Place the ginger biscuits in a food processor and process to fine crumbs. Place in the bottom of the tin. Mix the rest of the ingredients together in a food processor or using a hand whisk. Stir through some of the kumquat compote - you want to leave enough to decorate the top of the cake. Don't mix it in too much - you want a sort of ripple effect in the finished cake.

Place the cake in the oven, and bake for 45-55 minutes. If it starts to brown too much on top, cover with foil. It doesn't matter if it cracks a little - it's ready when it's firm and golden at the edges and still slightly wobbly in the middle. Leave to cool with the oven door open, then place in the fridge and chill.

Before serving, spoon the rest of the kumquat compote over the cake. Decorate with mint sprigs, dust with icing sugar, and serve.