Name: S'mores Molten Microwave Mug Cake
Total time: 25 min
Ingredients: 4 tablespoons unsalted butter; 1 ounce (28 grams) bittersweet chocolate , chopped; ¼ cup (1¾ ounces/50 grams) sugar; 2 large eggs; 2 tablespoons unsweetened cocoa powder; 1 teaspoon vanilla extract; ⅛ teaspoon table salt; ¼ cup (1¼ ounces/35 grams) all-purpose flour; ½ teaspoon baking powder; 6 marshmallows; 2 whole graham crackers , crushed into crumbs, plus 1 whole graham cracker, broken into quarters, divided

Why This Recipe Works

We wanted to incorporate the classic s'mores elements of marshmallow and graham crackers into chocolate mug cakes—individual cakes that are cooked in coffee mugs in the microwave—for a nearly instant dessert we could enjoy any time of year. To keep our cakes from overflowing, we found we had to supplement bittersweet chocolate with cocoa powder; because cocoa powder has less fat it produces less steam, thus decreasing the chance of an overflow. We tried making a graham cracker crust on the bottom of each mug, but it dissolved into the warm cake batter. Instead, we crushed the graham crackers and sprinkled the crumbs into an even layer for an attractive topping. Marshmallows grew pleasantly puffy in the microwave when placed atop the layer of cracker crumbs. For added decadence, we also pushed one into the center of each cake to create a molten core. Served with extra graham crackers as a fun garnish, our s'mores mug cakes were complete—no campfire required.

Before You Begin

We developed this recipe in a full-size, 1200-watt microwave. If you're using a compact microwave with 800 watts or fewer, increase the cooking time to 90 seconds for each interval. For either size microwave, reset to 50 percent power at each stage of cooking. Use a mug that holds at least 12 ounces, or the batter will overflow.

Instructions

Microwave butter and chocolate in large bowl at 50 percent power, stirring often, until melted and smooth, about 1 minute. Whisk sugar, eggs, cocoa, vanilla, and salt into chocolate mixture until smooth. Combine flour and baking powder in second bowl. Whisk flour mixture into chocolate mixture until combined. Divide batter evenly between 2 (12-ounce) coffee mugs.

Place mugs on opposite sides of microwave turntable. Microwave at 50 percent power for 45 seconds. Stir batter and microwave at 50 percent power for 45 seconds (batter will rise to just below rim of mug).

Press 1 marshmallow into center of each cake until top of marshmallow is flush with top of cake. Sprinkle each cake with 2 tablespoons graham cracker crumbs and top with remaining marshmallows, pressing to adhere to top of cake. Microwave at 50 percent power for 30 seconds to 1 minute (marshmallows should be softened and puffed). Let cakes sit for 2 minutes. Sprinkle with remaining graham cracker crumbs and garnish with graham cracker quarters. Serve.