Dough: 1/4 cup instant espresso powder 2 cups very hot milk, at 190 degrees F (88 degrees C) 2 1/4 tsp active dry yeast 1 large egg, beaten 2 tbsp white sugar 3/4 tsp fine salt 6 tbsp unsalted butter, melted 4 cups all-purpose flour Filling: 1/2 cup unsalted butter 3/4 cup brown sugar 1 tbsp instant espresso powder 1 tbsp unsweetened cocoa Icing: 1 1/4 cups powdered sugar 3 tbsp espresso/strong co…