|Make cake layers:
1.Preheat oven to 375°F. Grease 2 (8- by 2-inch) round cake pans and line the base with grease proof paper. Grease and dust the paper with flour, knocking out excess.
2. Sift together flour, baking soda, and salt. Stir together milk and lemon juice (mixture will curdle).
3. Beat butter and sugar with an electric mixer until pale and fluffy.
4. Add eggs 1 at a time, beating well after each addition. 5. Alternately add flour mixture and milk mixture in batches, beginning and ending with flour, mixing at low speed until just combined.
6. Divide batter between pans, smoothing tops. Bake in the oven for about 20 minutes or until a tester comes out clean. Cool in pans for 10 minutes, then invert onto racks, remove paper, and cool completely.
Beat cream with cleaned beaters until stiff peaks. Fold the whipped cream into lemon curd.
Put 1 cake layer, rounded side up, on a cake plate and spread with one fourth of frosting. Top with second layer round side up and spread top and sides with remaining frosting. Decorate with violets or cherries
Cake can be assembled 1 day ahead and chilled. Let stand at room temperature 30 minutes before serving.
This batter can be baked in 16 (1/2-cup) muffin cups about 15 minutes;
Whisk together juice, zest, sugar, and eggs in a heavy based saucepan. Stir in butter and cook over moderately low heat, whisking frequently, until curd is thick enough to hold marks of whisk and first bubble appears on surface, about 6 minutes.
Transfer lemon curd to a bowl, covered with plastic wrap and chill, until cold, at least 1 hour.
Curd can be chilled up to 1 week.
Makes about 1 1/3 cups.