enough for one (8-inch) 3-layer cake
1/2 cup plus 1 tablespoon creamy peanut butter
6 cups powdered sugar, sifted
1 1/2 teaspoons ground cinnamon
1 1/2 teaspoons ground nutmeg
3/4 cup milk
Cream peanut butter. Combine sugar, cinnamon, and nutmeg; add to creamed peanut butter alternately with milk. Beat on medium speed of electric mixer until mixture is smooth.