Croque Madame Waffle

Name: Croque Madame Waffle
Ingredients: 2 cups Bob's Red Mill Whole Wheat Pastry Flour; 1/2 teaspoon baking soda; 1 teaspoon baking powder; 1 teaspoon salt; 3 tablespoons sugar; 3 whole eggs beaten; 1 stick 1/2 cup unsalted butter, melted; 16 ounces buttermilk room temperature; For the Croque Madame:; 3 tablespoons unsalted butter; 3 tablespoons all-purpose flour; 2 cups milk; 12 oz. Gruyère grated; split; ½ cup finely grated Parmesan cheese + more for garnish; Kosher salt; to taste; freshly ground black pepper to taste; a pinch of freshly grated nutmeg; 6 waffles; already made; 6 tablespoons Dijon mustard; ham heated; 6 fried eggs; diced green onions for garnish