1. Preheat the oven to 170C/325F/gas 3. Butter and line with parchment a round 23cm (9in) tin – if it’s loose-bottomed, line the whole tin with foil, then with parchment, so the apricot juice doesn’t leak. Melt the butter for the cake and the topping (best melt a whole 250g pack – amazing how much water will evaporate). Leave to cool.
2. Toast the almond flakes until golden. Mix all the topping ingredients in a bowl, then spread at the bottom of the prepared tin.
3. Mix the milk with the vanilla extract. In a bowl, mix the flour with the baking powder. Place the sugar and eggs in a large bowl or a standing mixer bowl and beat until pale, fluffy, increased in volume significantly and forms ribbons when paddles are lifted. This will take about 5-7 minutes.
4. Add a third of the flour and mix in on low speed, then add a third of the milk, mixing continuously. Repeat twice more until all the flour and milk are used up. Mix in the melted butter, adding it in a slow stream.
5. Halve and stone the apricots and place them cut side down on the topping in the tin. Pour over the cake mix.
6. Bake for about 1 ¼ - 1hour 30 minutes until a skewer inserted in the middle of the cake comes out clean, and the surface springs back when pressed.
7. Cool in the tin for 30 minutes. Turn over onto a wire rack , remove the parchment and serve warm or cooled completely.