Dark Cocoa Buttermilk Cake with Cocoa Mascarpone Frosting

INGREDIENTS

Eggs

2 1/3 cups

All-purpose flour

3/4 tsp

Baking powder

1 tsp

Baking soda

1 cup

Brown sugar, packed

3/4 cup

Cocoa powder or unsweetened cocoa powder, Dutch-processed unsweetened

1 cup

Granulated sugar

Recipe cocoa mascarpone frosting

1/2 tsp

Salt

2 tsp

Vanilla

White and dark chocolate shavings

3/4 cup

Butter

1 1/2 cups

Buttermilk or sour milk