Mochaccino layer cake

Ingredients

• 1 2/3 cup flour
• 1 1/2 cup sugar
• 1/3 cup cocoa
• 1 1/2 teaspoon baking soda
• 1 teaspoon salt
• 1 teaspoon instant espresso-style coffee dissolved in ½ cup hot water
• 1 cup milk
• 100 grams melted butter
• 2 eggs
• Rum syrup (optional)
• 1/4 cup water
• 1/4 cup sugar
• 1/4 cup white rum
• Frosting
• 90 grams kremelta, at room temperature
• 90 grams butter, at room temperature
• 3 1/2 cup icing sugar
• 1 1/2 teaspoon instant coffee dissolved in 2 tablespoons hot water, then cooled
• 1 tablespoon milk
• decorations of choice