Instructions

1. Preheat the oven to 160°C.
2. Grease a round springform cake tin (about 20 cm) and line the bottom with baking paper.
3. Beat the butter with 100g caster sugar until creamy, then add the vanilla extract, lemon zest and mix well. Add the egg yolks one at a time, beating well between each addition.
4. Fold in the ground almonds and ricotta.
5. In an other bowl, whisk the egg whites until soft peaks form. Gradually add the remaining sugar and continue whisking until the peaks are firmer (but not too hard).
6. Fold a spoonful of the egg whites into the almond mixture, then gently fold in the rest until you get a smooth batter.
7. Spoon the batter into the greased cake tin and smooth out the top. Scatter the flaked almonds all over the top.
8. Put the tin in the middle of the oven and bake the cake for 40-50 minutes until lightly golden. The middle of the cake will be a bit wobbly but this will firm up when cooled.
9. Let the cake cool completely in the tin, the remove it from the tin.
10. Chill for a couple of hours, if preferred. Or serve it immediately, dusted with icing sugar, if liked.