For this week's Weekend Herb Blogging (hosted by Susan from The Well-Seasoned Cook), 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)
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.