Buttermilk Waffles with Homemade Strawberry Sauce

Name: Buttermilk Waffles with Homemade Strawberry Sauce
Ingredients: 3 large eggs, separated; Pinch cream of tartar; 1 cup buttermilk; 1/2 teaspoon vanilla extract; 2 tablespoons butter plus 1 tablespoon, melted; 1 cup unbleached all-purpose flour; 3 tablespoons brown sugar; 1/2 teaspoon salt; 1 teaspoon baking soda; 1/4 teaspoon baking powder; 1/2 teaspoon ground cinnamon; 1 quart strawberries, hulled and sliced; 1/4 cup sugar; 1/4 cup water; 1 lemon, zested and juiced; 1 tablespoon cornstarch; Powdered sugar, for topping