INGREDIENTS
1/2 cup
butter
20 oz
semisweet chocolate, divided (12 ounces chopped and 8 ounces cut into squares the size of the marshmallows, plus more for garnish if desired)
1 1/2 cups
flour
1/2 cup
cocoa powder
1 1/2 tsp
baking powder
1/4
teaspon salt
1 1/4 cups
light brown sugar
3
eggs, at room temperature
1 1/2 tsp
vanilla
18
marshmallows