2 eggs ((at room temperature))
3/4 cup buttermilk
1/4 cup plain greek yogurt
1/2 cup canola oil
1 tablespoon vanilla extract
1 1/2 cups all-purpose flour
1 1/2 cups granulated sugar
1 cup unsweetened cocoa powder
1 1/2 teaspoons baking soda
1 1/2 teaspoons baking powder
1 teaspoon salt
3/4 cup hot black coffee
1/2 cup semi-sweet chocolate chips ((optional))
3 sticks (1 1/2 cups) salted butter ((softened to room temperature))
3 cups powdered sugar
3/4 cup unsweetened cocoa powder
2 teaspoons vanilla extract
3-4 tablespoons heavy whipping cream