Dark & Sumptuous Chocolate Cake - cooking recipe

Ingredients

FOR THE ICING
60 ml cold water
75 g coconut butter (this is not the same as oil)
50 g soft dark sugar
1 1/2 teaspoons instant espresso powder
1 1/2 tablespoons unsweetened cocoa
150 g bittersweet chocolate, finely chopped (min. 70% cocoa solids, see Intro)
FOR THE CAKE
all-purpose flour
1 1/2 teaspoons baking soda
1/2 teaspoon fine sea salt
1 1/2 teaspoons instant espresso powder
75 g unsweetened cocoa
300 g soft dark brown sugar
375 ml hot water, from a recently boiled kettle (1 1/2 cups)
90 ml coconut oil
1 1/2 teaspoons cider vinegar or 1 1/2 teaspoons white wine vinegar
1 tablespoon edible rose petal
1 tablespoon pistachios, chopped

Preparation

Equipment: 8-inch round springform cake tin.
Start with the icing, though first preheat the oven to 180\u00b0C/350\u00b0F/gas mark 4 and pop in a baking sheet at the same time. Put all of the icing ingredients except the chopped chocolate into a heavy-based saucepan and bring to the boil, making sure everything's dissolved. Then turn off the heat - but leave the pan on the hob - then quickly add the finely chopped chocolate and swirl the pan so that it is all underwater, so to speak. Leave for a scant minute, then whisk until you have a darkly glossy icing, and leave to cool. I find this takes exactly the amount of time the cake takes to make, cook and cool. But do give the icing a stir with a spatula every now and again.
Line the bottom of your springform cake tin (you will need a good, leakproof one as this is a very wet batter) with baking parchment.
Put the flour, bicarb, salt and instant espresso and unsweetened cocoa in a bowl and fork to mix.
Mix together the sugar, water, coconut oil and vinegar until the coconut oil has melted, and stir into the dry ingredients, then pour into the prepared tin and bake for 35 minutes. Though do check at the 30-minute mark to see if it is already done.
When it's ready, the cake will be coming away from the edges of the tin and a cake tester will come out clean, apart from a few crumbs. This is a fudgy cake and you don't want to overdo it.
Once the cake is cooked, transfer the tin to a wire rack and let the cake cool in its tin.
Turn to your icing, and give it a good stir with a spatula to check it is at the right consistency. It needs to be runny enough to cover the cake, but thick enough to stay (mostly) on the top. So pour over the unmoulded cake, and use a spatula to ease the icing to the edges, if needed.
If you wish to decorate, now is the time to do it. In which case, sprinkle joyously with rose petals and chopped pistachios or anything else that your heart desires; otherwise, leave it gleaming darkly and, indeed, sumptuously. Leave to stand for 30 minutes for the icing to set before slicing into the cake.
FREEZE NOTE: The cake can be made ahead and frozen, without icing. When cool, carefully wrap cake in a double layer of clingfilm and a layer of foil. Freeze for up to 3 months. To defrost, unwrap and place on a serving plate at room temperature for 3-4 hours.