Rose Gray, Ruth Rogers
By Rose Gray and Ruth Rogers
Preheat the oven to 160°C/325°F/Gas 3. Butter and flour a 30 cm (12 in) cake tin.
Beat the butter and sugar together until pale and light. Stir in the ground almonds and vanilla. Beat in the eggs, one at a time. Fold in the lemon zest and lemon juice, the polenta, baking powder