FOR THE CHOCOLATE CAKE: – 2 & 1/4 cups (270g) all-purpose flour – 1 & 1/2 cups (300g) granulated sugar – 1/2 cup (42g) cocoa powder – 2 teaspoons baking soda – 1 teaspoon baking powder – 1/2 teaspoon salt – 1 cup (236ml) buttermilk – 1/2 cup (118ml) vegetable oil – 3 large egg – 1 teaspoon peppermint extract – 1 teaspoon vanilla extract – 1 cup (236ml) hot water FOR THE PEPPERMINT BUTTERCREAM: – 1 cup (226g) unsalted butter, softened – 3 tablespoons heavy cream – 1 teaspoon peppermint extract – 1/2 teaspoon vanilla extract – 3 cups (330g) confectioners' sugar – crushed peppermints, for garnish