Method

1. Preheat the oven to 220C/425F/Gas 7.
2. Grease a medium-sized cake tin (approx 6-8in/20cm) with the butter.
3. Cream the sugar and unsalted butter together in a food processor. Add the eggs and flour and pulse to combine.
4. Arrange the lemon slices on the base of the cake tin. Sprinkle with the almonds and then pour the sponge mixture over.
5. Bake in the oven for 15-20 minutes, or until golden and springy to the touch.
Leave to cool and then turn out onto a cooling rack.
6. Cut into slices and serve with a spoonful of yoghurt and mint sprigs.