St.Patrick’s Stout Chocolate Layer and Irish cream buttercream Cake

This is by far the easiest chocolate Stout cake you will find Starting with box cake mix  And supper simple Irish cream,  buttercream you will plenty of time to focus on dinner. your guest will think that you spent hours prepping for a wonderful St. Patrick’s day dinner celebration
1 box Betty  devil’s food cake mix
1 1/4cups stout beer
1/3 cup vegetable oil
3 Eggs
Heat oven to 350°F (325°F for dark or nonstick pans). Grease bottoms only of three 9- or 8-inch round cake pans. Make cake batter as directed on box, using a cake mix, beer, the oil, and eggs. Pour about 1 1/2 cups batter into each pan.
 Bake 18 to 22 minutes or until a  toothpick inserted in center comes out clean. Cool 10 minutes before removing from pans. Cool completely
Irish cream Buttercream
 3     eggs
1/2   cup shortening
1/2  cup butter softened
1    box  (1 lb) powdered sugar (4 cups)
1   teaspoon vanilla
 3to 4 tablespoons Irish cream liquor
In a large bowl, beat shortening and butter with electric mixer on low speed until smooth. Gradually add powdered sugar, 1 cup at a time, beating until combined. Add vanilla and 2 tablespoons of the liqueur; beat until blended. Add enough of the remaining 1 to 2 tablespoons liqueur, 1 teaspoon at a time, beating until frosting is light and fluffy.
Decorate as desired