Preheat oven to 350°F.
Grease two 9-inch square baking pans.
Combine cake mix, sour cream, water, eggs, lemon peel and spices in large bowl with electric mixer at low speed until ingredients are moistened.
Beat at high speed 2 minutes, scraping side of bowl frequently.
Stir in 1 cup pecans.
Divide batter evenly between prepared pans.
Bake 25 to 30 minutes or until wooden toothpick inserted in centers comes out clean.
Cool in pans 10 minutes.
Remove from pans to wire racks; cool completely.
Place one layer on serving plate.
Spread with 1/3 of frosting.
Top with second layer.
Frost sides and top of cake with remaining frosting.
Garnish with additional pecans, if desired.
Store tightly covered at room temperature.