Coca-Cola Cake

Ingredients

• baking spray
• 2 cups (about 10 ounces) all-purpose flour
• 1 cup sugar
• 1 cup packed dark brown sugar
• 3/4 teaspoon salt
• 16 tablespoons (2 sticks) unsalted butter
• 1/4 cup natural cocoa powder
• 1 cup coca-cola
• 1 teaspoon baking soda
• 1/2 cup buttermilk, at room temperature
• 2 large eggs, at room temperature and lightly beaten
• 1 teaspoon pure vanilla extract
• 2 cups miniature marshmallows
• 8 tablespoons (1 stick) unsalted butter, at room temperature
• 1/4 cup natural cocoa powder
• 6 tablespoons coca-cola
• 16 ounces confectioners’ sugar, sifted
• 1/4 teaspoon salt
• 1 teaspoon pure vanilla extract
• 1 cup pecans, toasted and coarsely chopped (optional)