- 1 (9 ounce) package yellow cake mix
- FILLING:
- 3 tablespoons sugar
- 3/4 teaspoon butter or margarine, softened
- 1/4 teaspoon grated lemon peel
- 1 drop yellow food coloring
- 4 1/2 teaspoons lemon juice
- FROSTING:
- 3 tablespoons butter or margarine, softened
- 1 1/2 cups confectioners' sugar
- 1 teaspoon lemon juice
- 1 teaspoon finely grated lemon peel
- 1 tablespoon milk
- Prepare cake mix according to package directions; pour into a greased 9-in. square baking pan. Bake at 350 degrees F for 18-20 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pan to a wire rack to cool completely.
- For filling, combine the sugar, cornstarch and salt in a saucepan. Gradually stir in water until smooth. Bring to a boil; cook and stir for 2 minutes or until thickened. Remove from heat; stir in butter, lemon peel and food coloring if desired. Gradually stir in lemon juice. Cool completely.
- For frosting, in a mixing bowl, beat butter until fluffy. Gradually add confectioners' sugar. Add lemon juice, peel and enough milk to achieve spreading consistency.
- To assemble, cut cake in half. Trim outside edges. Place one half on a serving plate. Spread with the lemon filling. Top with remaining cake; spread with frosting.