Mashed Potato Chocolate Cake

Mashed potatoes in chocolate cake sounds like a dare, but it’s actually an old Depression-era trick for stretching ingredients while making the moistest cake imaginable. The starch in the potatoes traps moisture that flour alone can’t hold, giving you a crumb so dense and fudgy it barely needs frosting.

Three squares of unsweetened chocolate get melted into milk on the stovetop, then cooled before going into the batter. Don’t skip the cooling. Hot chocolate mixture will melt the margarine too fast and throw off the texture.

The real lift in this cake comes from the egg whites. Beaten stiff with a quarter cup of sugar, they get folded in at the end. That folding has to be gentle. You’re keeping all those air bubbles intact so the cake rises light despite the heavy potato in the batter.

Pro Tips

• Use cold, firm mashed potatoes, not warm or loose. Runny potatoes add too much moisture and the cake won’t set.
• Beat egg whites in a clean, dry bowl. Any trace of grease or yolk and they won’t whip to stiff peaks.
• Fold the egg whites into the batter in two additions. The first batch loosens the batter so the second folds in without deflating.
• Let the chocolate-milk mixture cool to room temperature before combining. Patience here prevents a greasy, broken batter.

Variations

• Frost with a simple chocolate ganache for double chocolate impact.
• Add 1 teaspoon of instant espresso to the chocolate-milk mixture to deepen the chocolate flavor.
• Fold in ½ cup mini chocolate chips for pockets of melted chocolate throughout.