Prepare the chocolate cake mix according to package directions.
As the cupcakes are cooling, prepare the chocolate-covered strawberries.
Wash, dry and remove the green stem from the strawberries.
Line a baking sheet with parchment paper and set aside.
Melt the milk chocolate chips in the microwave in 35 second increments, stir well in between each reheating.
Dip each strawberry in the melted chocolate chips, coating the strawberries completely. (A toothpick or dipping tool comes in handy for this.)
Place the chocolate-coated strawberries on the prepared baking sheet and repeat the process with all strawberries.
Allow the chocolate on the strawberries to set for at least 45 minutes.
For the strawberry buttercream, beat the butter and powdered sugar in a large bowl with an electric mixer for 2 minutes.
Add the milk and strawberry extract and beat until combined.
Adjust the texture or flavor of the frosting, as needed, with additional sugar, milk or strawberry extract.
Scoop the buttercream into a piping bag fit with a large star tip.
Swirl the strawberry buttercream onto the cooled chocolate cupcakes and top each cupcake with a chocolate-covered strawberry.