For a deeper chocolate flavor, replace 1–2 tablespoons of the flour with extra cocoa powder and add an extra tablespoon of sugar to keep the sweetness balanced. If you like a softer, more cake-like texture, stir 2–3 tablespoons of milk into the batter at the end until it drops easily from the spoon. For a classic Midwestern touch, fold a handful of mini chocolate chips into the filling before spreading. Around the holidays, you can add 1/2 teaspoon of peppermint extract to the filling and roll the edges of the assembled pies in crushed peppermint candies. If you’re baking for a smaller household, make mini whoopie pies by dropping teaspoon-sized mounds of batter and baking a minute less; they’re easier to tuck into lunch boxes or share at coffee hour. The cakes also freeze well on their own—stack them with parchment between layers, then thaw and fill when you need a fast special-occasion treat, just as Grandma Ruth liked to do.
Grandma Ruth swore this was the fastest way to make a treat feel like a special occasion.
