Preheat the oven to 170C Fan and grease and line a 23 cm loose-based round tin with non-stick baking paper.
In a large bowl (or a stand up mixer with the whisk attachment) whisk together the ricotta and the olive oil until smooth.
Add the vanilla and the sugar and whisk for a further 2 minutes. Next, add the eggs, one at a time, whisking until the batter is completely smooth.
In a separate bowl, sieve together the flour and baking powder. Add the ground almonds and salt, then whisk gently to combine. Fold into the batter ⅓ at a time until smooth.
Add the lemon zest and half of the raspberries, mixing gently until evenly distributed throughout.
Pour into the prepared tin and spread in a smooth and even layer. Top with the remaining raspberries and sprinkle with the flaked almonds.
Bake for 45- 50 minutes or until golden on top and just firm to touch.
Leave to cool in the tin for at least 15 minutes before turning out onto a wire rack to finish cooling completely.
Dust with sieved icing sugar before serving.