Allow butter and eggs to stand at room temperature 30 minutes. Generously grease and flour six 4-inch fluted tube pans or one 6-cup fluted tube pan. Combine flour, baking powder, and nutmeg; set aside.
In a large mixing bowl beat butter with electric mixer on medium speed for 30 seconds. Beat on medium-high speed, adding the 3/4 cup granulated sugar, 2 tablespoons at a time, about 6 minutes or until mixture is very light and fluffy.
Stir in the 1/4 cup amaretto, lemon peel, and vanilla. Add eggs, 1 at a time, beating for 1 minute after each additional and scraping bowl often. Gradually add flour mixture to egg mixture, beating on medium-low speed just until combined. Pour into prepared pans.
Bake in a 325 degree F oven for 20 to 25 minutes for the 4-inch pans (40 to 45 minutes for the 6-cup fluted pan) or until a wooden toothpick inserted near the center(s) comes out clean. Cool in pans on wire racks for 10 minutes. Remove from pans. Cool thoroughly on rack(s). Prick fluted top and sides of each cake generously with tines of a fork.
For syrup, in a medium saucepan combine the 1/3 cup granulated sugar, the water, brown sugar, and corn syrup. Cook and stir over medium heat until bubbly and most of the sugar is dissolved; remove from heat. Stir in 1/2 cup amaretto. Cool for 5 minutes.
Dip fluted top and sides of each cooled 4-inch cake into syrup. Place cakes on wire racks above a large tray or baking sheet. Spoon or brush as remaining syrup over tops of cakes. (If using 6-cup pan, do not dip cake into syrup. Place cake on wire rack over tray or baking sheet; spoon or brush syrup over top and sides of cake, reusing syrup on tray.) Cool cake(s).
Wrap cakes individually in plastic wrap or cellophane; shill, fluted side up, for up to 3 weeks. (or, transfer to a tightly covered container and chill for up to 3 weeks.) Makes 24 servings.