Blueberry and elderflower upside-down cake

[Just a quick - and excited! - note to say that I've been nominated for Best Food Blog in the Cosmopolitan Blog Awards 2012!]

I'm pretty sure that there has never been an occasion over the last three years when I haven't had at least one punnet of blueberries either in my fridge or freezer. I would hoard them obsessively during my time at Oxford, where they could regularly be found at the Wednesday market priced at a mere pound. Given that I've seen punnets fetching up to £4.49 in Marks & Spencer, this was a pretty bargainous find. (Luckily I have a mother who insists on blueberries with her morning muesli, so we now have a constant supply in the fridge, which I don't have to pay for - win). I'd stash them away for a later date, a date which actually rarely happened to be much later, because the uses for blueberries in my kitchen are numerous. 

I like to use them to stud a moist, squidgy loaf of banana bread, perfuming the crumb and creating sweet little pockets of purple. Continuing the banana theme, they also work well folded into banana pancake batter, or simmered gently in a pan until their skins burst and they release tart inky juices, which can then be spooned dramatically over a pile of pancakes. I also use them in every variation of this baked oatmeal I make - sometimes the chewy crust hides a hot-pink bed of tart, tender rhubarb, sometimes a comforting blanket of baked banana, and sometimes a marigold shock of jammy soft apricot slices, but there are always blueberries infusing their mild sweetness into that molten fruity puddle.

I like them folded through hot, bubbling porridge, engulfed in its nutty, milky blanket, sending ribbons of juice twisting through the creamy canvas like capillaries. They work well in this context with all fruits, but particularly - again - chopped banana, or grated apple. 

They're also rather good in savoury dishes, for example as a sauce for venison steaks, and sometimes I use them instead of pomegranate seeds to add a welcome burst of sweetness to a wild rice or couscous salad with shredded duck or chicken. 

Yet I rarely bake with blueberries. Maybe I consider them too obvious - I generally like to bake vaguely unusual things with tragically underrated fruits, such as rhubarb and gooseberries. In fact, maybe that should be my blog's new tagline.

'Nutmegs, seven. Baking vaguely unusual things with tragically underrated fruits.'

Catchy, no?

I was leafing through this month's delicious magazine when I came across Signe Johansen's recipe for blueberry and elderflower cake. It's taken from her latest book, Scandilicious Baking, and I was drawn in both by the title - a combination I'd never come across before, having only used elderflower with gooseberries - and the enticing photo, depicting a rustic-looking wedge of cake topped with a juicy, dimpled purple carpet of squishy berries. The colours really struck me - such an intense, vibrant blue-purple, a hue you very rarely see in food. 

Today, in need of a summery cake to combat the distinctly un-summery torrential rain occurring outside my kitchen window, I put on my apron, rolled up my sleeves, unearthed several punnets of blueberries from the freezer, and got to work.

This is an upside-down cake. The blueberries are scattered over the base of a cake tin, drizzled with elderflower cordial, left to steep while the cake mixture is made, then covered with a layer of batter before being baked. After its spell in the oven, you turn it over to reveal a beautiful purple topping that has soaked down into the crumb, as if the whole thing has been drenched wantonly in ink.

I made a few changes to Signe's recipe, using a sponge recipe that I came up with myself and always use in upside-down cakes, mainly because it uses a lot less butter than standard recipes but still tastes incredible, therefore I can justify eating more cake. (Right?) However, it actually relates pretty closely to her original, just with fewer eggs and less butter and sugar. I added ground almonds to my cake mixture, as she does, for a light texture and to help give a moist crumb. I also used spelt flour, as she suggests, because I think it lends a lovely nutty texture to the finished cake, which is a great contrast with the sweet, vibrant fruit.

This emerged from the oven everything I hoped it to be. The crumb has a really lovely mellow flavour to it, from the use of yoghurt in the sponge and from the almonds and hint of vanilla. It tastes robust, somehow, because of the spelt flour - subtly nutty, with a hint of biscuit about it. It has the perfect light, crumbly texture. The blueberries burst and drench the cake in their sweet juices, lightly perfumed by the elderflower cordial, giving a delicious contrast in both texture and flavour. Rich, earthy cake, and juicy, sweet berries.

Above all, I just love the look of this cake. It's so vibrant and joyful; just the thing to perk up a somewhat lacklustre British summer. The berries glisten in a jewel-like fashion; dark, inky and mysterious. Fresh from the oven, it is exquisite with a cup of tea in the afternoon - it's substantial enough to raise your energy levels and fill that sad gap between lunch and dinner, and it's not too sugary or sweet so still feels vaguely nutritious. It's also delicious served warm with ice cream for dessert.

I'm ashamed to admit this, but I ate half of this entire cake in one day. That's how good it is.

Blueberry and elderflower upside-down cake (serves 6-8):

  • 200g blueberries
  • 50ml elderflower cordial
  • 50g soft butter
  • 2 eggs
  • 150g caster sugar
  • 1 tsp baking powder
  • 160g spelt flour
  • 40g ground almonds
  • A pinch of salt
  • 1 tsp vanilla extract
  • 200ml plain yoghurt

Grease an 18-22cm springform cake tin with butter (I used an 18cm tin, but a 20/22cm tin would also work fine, it will just give you a shallower cake). Tightly wrap a piece of foil around the outside edge of the tin to prevent any juices escaping. Scatter the blueberries over the base and pour over the elderflower cordial. Toss them together and leave them to soak.

Pre-heat the oven to 170C/160C fan oven. Put an oven tray under the shelf you'll be baking the cake on, just in case some of those lovely purple juices do escape.

Mix together the butter and caster sugar in a large bowl using an electric whisk until light and fluffy. Add the eggs one at a time, beating well. Sift in the flour, baking powder and ground almonds then add the salt and vanilla. Fold in until you get a stiff dough, then mix in the yoghurt to form a soft batter.

Ensure the blueberries are arranged in a fairly even layer over the bottom of the tin, then top with the cake mixture. Bake in the oven for 40-60 minutes (a smaller tin will mean a thicker cake, which will mean longer in the oven) - it's ready when a skewer comes out clean, or when the top springs back when pressed and isn't wobbly inside.

Leave to cool for five minutes in the tin, then run a knife around the outside of the cake. Open the side of the springform tin, then put a plate over the top. Carefully invert the cake and remove the base layer of the tin to reveal gorgeous moist inky berries. Serve warm, with a cup of tea or some ice cream.