Chocolate Lava Nutella Cookies

INGREDIENTS

1/2

cup unsalted butter, softened (1 stick)

heaping 1/3 cup Nutella (stir well before adding)

1/2 cup

light brown sugar, packed

1/4 cup

granulated sugar

large egg

2 tsp

vanilla extract

1 3/4 cups

all-purpose flour

2 tsp

cornstarch

1 tsp

baking soda

salt, optional and to taste

1 cup

semi-sweet chocolate chips

12 1/4

-ounce chunks dark chocolate, divided (one chunk per cookie; I used Trader Joe’s 72% Pound Plus bar and 1/4-ounce is half of one square)