Chocolate Covered Chocolate Cake Truffles

1 (18.25 ounce) box devil's food cake mix
1/2 cup butter
1/2 cup cocoa powder
1/2 cup confectioners' sugar
1/2 cup finely chopped hazelnuts
3 tablespoons Bailey's Irish Cream
16 ounces semisweet chocolate

Spray a 9 x 5-inch loaf baking pan with nonstick spray.

Prepare and bake cake according to package instructions. Let cool.

Melt butter in saucepan, stir in cocoa powder and sugar. Add nuts and liqueur. Remove from heat. Crumble cake into mixture in saucepan and mix by hand until well blended. Roll into 1 1/2-inch balls.

Melt chocolate in bowl in microwave (add 1 teaspoon vegetable oil to thin if necessary). Dip balls one at a time, covering completely.

Place on wax paper to dry. Store, covered in a cool, dry place.