Preheat oven to 350°F. Grease a Bundt pan.
In a large bowl, combine cake mix, water, oil, eggs, and 1/4 cup Limoncello. Beat for 2 minutes.
Pour batter into prepared pan. Bake for 35–40 minutes until a toothpick comes out clean.
Cool in pan for 15 minutes, then invert onto a wire rack to cool completely.
Mix powdered sugar, lemon juice, and 1 tablespoon Limoncello until smooth.
Drizzle glaze over cooled cake.