Chocolate-Peanut Butter Mug Cakes

• 1/3 cup all-purpose flour
• 3 tablespoons Dutch-processed cocoa, sifted
• 1/2 teaspoon baking powder
• 1/4 cup granulated sugar
• 1/4 cup packed light brown sugar
• 1/4 cup whole milk
• 1 tablespoon vegetable oil, such as avocado
• 1 1/2 teaspoons instant espresso powder
• 1 teaspoon vanilla extract
• 1 large egg
• 2 1/2 tablespoons creamy peanut butter, divided

Vanilla ice cream

• Chopped salted cocktail peanuts and flaky sea salt, for garnish

1. Whisk together flour, cocoa, and baking powder in a small bowl until well combined. Whisk together granulated sugar, brown sugar, milk, oil, espresso powder, vanilla, egg, and 1 1/2 tablespoons peanut butter in a medium bowl until well combined. Whisk flour mixture into sugar mixture until mostly smooth and well combined (some very small lumps are okay).
2. Divide batter evenly between 2 (12-ounce) microwavable mugs. Evenly divide and dollop remaining 1 tablespoon peanut butter in center of batter in each mug.
3. Microwave cakes, 1 at a time, on HIGH until tops are just set and a wooden pick inserted into center comes out with just some moist crumbs, 50 seconds to 1 minute and 10 seconds. (If cake is still underdone after 50 seconds, microwave on HIGH in 5- to 10-second intervals, as needed [see Note]; it’s normal for cake to rise and then sink slightly once removed from the microwave). Wipe sides and rims of mugs clean using a damp paper towel, if desired. Let cake stand at room temperature 5 minutes.
4. Top each cake with a scoop of ice cream. Garnish with peanuts and flaky sea salt.