Grease a 15x10x1-inch baking pan; line pan with waxed paper. Grease and lightly flour paper; set aside. In a small bowl stir together flour, cream of tartar, and baking soda; set aside.
In a medium mixing bowl beat butter with an electric mixer on medium speed for 30 seconds. Gradually beat in granulated sugar until well combined. Alternately add flour mixture and milk to butter mixture, beating on low speed after each addition just until combined.
Wash and dry beaters thoroughly. In a large mixing bowl beat egg whites with an electric mixer on medium speed until stiff peaks form (tips stand straight). Stir a small amount of egg whites into cake batter to lighten; fold batter into remaining egg whites.
Spread batter evenly into prepared pan. Bake in a 350 degree oven for 12 to 15 minutes or until a wooden toothpick inserted near the center comes out clean. Loosen sides. Immediately invert onto a clean kitchen towel sprinkled with powdered sugar; remove pan and waxed paper. Cool cake completely. Cut cake crosswise into three 10x5-inch rectangles.
Meanwhile, in a small bowl combine nuts with 2 tablespoons of the honey and 1 teaspoon of the lemon peel. Set aside.
In another small bowl combine figs, remaining 2 tablespoons honey, and remaining 1 teaspoon lemon peel.
To assemble, place one cake rectangle on a platter. Spread nut mixture on cake layer. Carefully top with one-third of the frosting, allowing frosting to flow over edges. Top with second cake layer. Spread fig mixture on second cake layer. Carefully top with another third of the frosting. Top with third cake layer. Spread with remaining frosting, allowing it to flow over edges. Sprinkle top of cake with toasted coconut chips. Let stand 2 hours before serving; or cover and chill overnight. Makes 12 servings.
In a large mixing bowl combine egg product, lemon juice, honey and vanilla. Gradually beat in powdered sugar until frosting is a slightly flowing consistency.