Ingredients:

• Butter, for greasing the pan
• 2 cups (242g) all-purpose flour
• 1 cup (120g) unsweetened Dutch processed cocoa powder
• 1 1/2 teaspoons baking powder
• 1 1/2 teaspoons baking soda
• 1/4 teaspoon salt
• 3/4 cup (177ml) hot water
• 2 tablespoons (30g) instant coffee powder or instant espresso powder
• 2 large eggs
• 1 cup (220g) sugar
• 1/2 cup (100g) brown sugar, lightly packed
• 1 cup (260g) mayonnaise
• 1 tablespoon vanilla extract
• 1/2 cup (80g) finely chopped semisweet or bittersweet chocolate
• 1/2 cup (113g) unsalted butter
• 2 tablespoons (30g) unsweetened Dutch processed cocoa powder
• 1 cup (130g) powdered sugar
• 1/2 cup heavy cream