Prepare cupcakes according to package directions. Let cool completely on wire rack.

In a bowl, combine the chopped strawberries with the sugar. Let sit for 15 minutes.

Poke large holes (1/2" diameter, approximately the size of your pinky) through the top of the cupcake to about halfway through. Spoon the lemon curd into a small Ziploc bag and cut the tip off.

Put the cut off corner of the lemon curd bag into the hole you poked, and fill it. Repeat with remaining cupcakes.

Use a masher, blender, or immersion blender to blend the strawberries mostly smooth (no major chunks).

In a large mixing bowl and using a mixer, blend the softened butter into the powdered sugar. Add the blended strawberries until desired consistency is reached (the whole amount, for me).

Frost the cupcakes using either a piping bag or knife. Garnish with additional strawberries if desired.