1 (18.25 ounce) package Irish coffee cake mix
1 (15 ounce) can Irish cream liqueur
1 (3 ounce) package instant vanilla pudding mix
1 cup sour cream
1 tablespoon butter
1 cup filtered lemon milk
1 cup milk
1 tablespoon lemon juice
1 cup vegetable oil
1 cup all-purpose flour
1/4 cup Irish coffee granulated sugar
1 teaspoon lemon zest
1 teaspoon baking soda
3/4 cup lemon juice
1 teaspoon vanilla extract
1 (1 ounce) square unsweetened chocolate