Whole Milk: Substitute the water in the recipe on the side of the box with milk for a dense texture.
Sour Cream: Add the ingredients as directed, then include two dollops of sour cream to make the cake extra moist.
Pudding: Want to kick up the flavor? Combine 2 tablespoons of instant pudding powder (vanilla for vanilla cake, chocolate for chocolate cake) with ½ cup water or milk, 3 eggs, and 1/3 cup vegetable oil.
Mayonnaise: Substitute the oil in the cake mix recipe with 1 cup of (yep) mayo. Don’t knock it ’til you’ve tried it.
Coffee: If you love chocolate-covered coffee beans, this one’s for you. Try substituting brewed coffee for water the next time you make a boxed chocolate cake.
Lemon: Squeeze half a lemon and grate 2 tablespoons of zest into your yellow cake mix, then add the other ingredients, as usual, to give it a tart kick.
Butter: Swap melted butter for vegetable oil to get that “this took three hours to make” taste. (It’ll take only about 30 minutes.)