Coat a 10-inch tube pan with cooking spray; dust with breadcrumbs.
Lightly spoon the flour into dry measuring cups, and level with a knife. Combine the flour, baking powder, salt, and mace in a bowl, and stir well with a whisk. Combine the mashed banana, milk, and banana liqueur in a bowl. Beat the butter in a large bowl at medium speed of a mixer until light and fluffy. Gradually add the granulated sugar and vanilla extract, and beat the mixture until well-blended. Add the eggs, 1 at a time, beating well after each addition. Add the flour mixture to the sugar mixture alternately with the banana mixture, beating at low speed, beginning and ending with the flour mixture.
Spoon the batter into prepared pan. Bake cake at 350° for 1 hour or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes on a wire rack; remove from pan. Cool completely on wire rack. Sift powdered sugar over top of cake.
Note: To freeze extra pound cake, let cake cool completely on a wire rack; then cut into individual slices. Place unglazed slices in a heavy-duty zip-top plastic bag. Remove excess air from the bag; then seal and place it in your freezer for up to four months. To thaw, let it stand at room temperature. Drizzle glaze per recipe's directions.
Note: You can use a 12 cup Bundt pan instead of the 10-inch tube pan. Just reduce the oven temperature to 325º.
I used nutmeg and allspice, also substituted stevia for the sugar. I should have inverted the pan while it was cooling, because it compressed in on itself, but was still very tastey. I will make this again.