Preheat oven to 160°C fan. Grease or line a 23cm round cake tin or springform tin. Add milk, sugar, lemon zest and vanilla to a small saucepan and warm over low heat, stirring until sugar has dissolved (do not boil). Add oil, stir; turn off heat.

Whisk eggs well in a bowl. Sift in dry ingredients, then pour in milk mixture and whisk well to form a smooth and runny batter. Pour into prepared tin and scatter blueberries evenly over the top. Bake for 30-40 minutes, until golden and a skewer inserted into the centre comes out clean. The cake should have risen a little and be airy and spongy in texture. Leave to cool for a while in the tin, then remove and place on a wire rack. Serve warm or cold, with ricotta or cream. Serves 6-8