Stir together first 3 ingredients; press into bottom of a well-greased 9-inch pieplate.
Bake at 350° for 10 minutes. Cool on a wire rack.
Bring mincemeat and 1/2 cup water to a boil in a small saucepan; boil 3 minutes. Cool. Spread mixture into crust.
Stir together ice cream and next 4 ingredients; spread over mincemeat. Freeze 8 hours. Remove from freezer, and let stand 20 minutes before serving. Garnish, if desired.
