Nutella Stuffed Chocolate Whoopie Pies

INGREDIENTS

Chocolate whoopie pies:

1/2 cup

or 1 stick) unsalted butter, softened

3/4 cup

brown sugar

1/4 cup

granulated or caster sugar

large egg

1 tsp

vanilla extract

1 tsp

baking soda

and 3/4 cup (245 grams) plain flour

1/2 cup

cocoa powder

3/4 cup

buttermilk

Nutella frosting:

1/2 cup

or 1 stick) unsalted butter, softened

3 cups

) icing or powdered sugar

1 tsp

vanilla extract

3/4 cup

Nutella

2 tbsp

milk