Line 2 baking sheets with parchment or lightly grease.
Punch down dough and place on lightly floured surface.
Divide the dough into 12 equal pieces.
Form each piece into a smooth round and place on prepared baking sheet about 3 inches (7.6 centimeters) apart.
Divide each sugar crust dough half into 6 equal pieces to create 12 pieces in all.
Brush the tops of the buns with additional melted butter.
Roll one sugar crust dough piece into a ball and place between two pieces of plastic wrap or wax paper. Press into a thin circle.
Carefully remove the circle from the plastic and place over the butter-brushed bun, pressing down gently to make sure it is attached to the bun.
Repeat with the remaining pieces.
Use a sharp knife to cut angled lines or criss-cross patterns into the circles to resemble seashell shapes. Take care not to cut into the bread.
Cover the baking sheets and allow to rest at room temperature until the bread is puffed, 1-2 hours.
Preheat oven to 350˚F (180˚C).
Bake in the preheated oven until golden on the bottom, rotating the baking sheets halfway through, about 20 minutes total.
These Conchas are best the day they are baked.