1 box Betty Crocker® SuperMoist® yellow cake mix
1/2 cup water
1/2 cup dry champagne
1/2 cup vegetable oil
2 teaspoons grated lemon peel
1/4 cup lemon curd (from 10-oz jar)
1 tablespoon sour cream
2 cups powdered sugar
2 tablespoons butter, melted
3 tablespoons fresh lemon juice
Heat oven to 350°F (325°F for dark or nonstick pan). Line 15x10x1-inch pan with foil. Spray with cooking spray.
Make cake batter as directed on box, using cake mix, water, champagne, oil and eggs. Stir 2 teaspoons grated lemon peel into batter. Pour into pan.
Bake 17 to 23 minutes or until toothpick inserted in center comes out clean. Do not remove cake from pan. Cool completely, about 1 hour. Place pan of cake in freezer. Freeze until firm, about 1 hour.
In small bowl, mix lemon curd and sour cream until well blended. Set aside.
To assemble cupcakes, remove cake from freezer; using foil, lift cake from pan. Using 2 1/4-inch round biscuit cutter, cut 24 rounds from cake. Place 12 rounds top side down. Spread each with about 1 teaspoon lemon curd filling. Top with remaining cake rounds, top side up.
In medium bowl, mix powdered sugar, melted butter and lemon juice until well blended. Spoon about 1 tablespoon icing over each cake, allowing icing to run down sides of cake.
To serve, place each cake in decorative cupcake liner, and garnish with lemon peel curls, if desired.