Butter a 20-23cm round cake tin. If it has a loose bottom, you will need to wrap the outside with foil to prevent any of the caramel from leaking. Heat the oven to 200C/180C fan/gas 6. For the apricots, put the granulated sugar and 75ml water into a saucepan. Heat slowly until the sugar has dissolved. When the sugar has melted, bring to the boil and watch the syrup until it starts to turn to a deep amber colour. Remove from the heat and add the butter. Stir until it has melted. Pour into the tin, then lay the apricots in it, cut-side down.
For the cake, beat together the butter and sugar until light with an electric whisk. Add the egg a little at a time, then the zest and almond extract. Mix all the dry ingredients together, then fold them gradually into the egg mixture, alternating with the milk. Spoon this over the apricots and bake for 50 mins. To test it’s baked, push a skewer into the centre. It should come out clean.
Leave the cake to cool for 15 mins, then run a knife in-between the cake and the inside of the tin and invert it onto a plate. If any of the apricot halves get left behind in the tin carefully scoop them up – trying to keep their shape intact and not squash them too much – and put them back, cut-side up, on the cake. Leave the cake to cool, or serve warm if you want.
Heat the apricot jam with 2 tbsp of water. Once the jam has dissolved, push it through a sieve to remove the bits of apricot. Leave it to cool a little – otherwise it overcooks the apricots, which should be perfectly cooked and not collapsing – then paint the jam thickly on the top of the cake. Leave this to set a little, then serve with crème fraîche or cream, if you like.