Peanut Butter Cup Chocolate Cupcakes with Toasted Peanut Butter Meringue Frosting

Preheat oven to 325 degrees F (165 degrees C). Line 14 muffin cups with paper liners. (5 minutes)

In a large bowl, whisk together the flour, 1 cup sugar, cocoa powder, baking powder, baking soda, and salt. Add the milk, vegetable oil, egg, and vanilla extract. Using an electric mixer on low speed, mix until just combined. Increase speed to medium and mix well. (5 minutes)

Reduce mixer speed to low and slowly pour in the boiling water. Increase speed to medium and beat for 1 minute. The batter will be thin. (2 minutes)

Fill each muffin cup halfway with batter. Place a peanut butter cup in the center of each. (5 minutes)

Bake in the preheated oven until golden and the tops spring back when lightly pressed, about 20 minutes. Remove from oven and cool in the pan for 5 to 10 minutes. Transfer to a wire rack to cool completely before frosting. (30 minutes)

Position an oven rack about 6 inches from the heat source and preheat the broiler.

In a heatproof bowl, whisk together the egg whites and 1 cup sugar until just combined. Pour the mixture into a small saucepan and heat over medium heat, stirring constantly, until the sugar is dissolved and the mixture is warm to the touch. Return the egg white mixture to the heatproof bowl. (10 minutes)

Using an electric mixer, whisk the egg white mixture on high speed until stiff, glossy peaks form. (5 minutes)

Place the peanut butter in a microwave-safe bowl. Heat on high in 15-second intervals, stirring in between, until melted and smooth. Gently fold the melted peanut butter into the meringue. Transfer the peanut butter meringue frosting to a piping bag fitted with a decorative tip. (5 minutes)

Pipe the frosting onto the cooled cupcakes in a generous swirl. (5 minutes)

Toast the cupcakes under the preheated broiler until the meringue is lightly browned, about 1 minute. Watch carefully to prevent burning. (2 minutes)