The Gilded Springerle

Name: The Gilded Springerle
Ingredients: 1/2 teaspoon hartshorn or baking powder; 2 tablespoons buttermilk or milk; 6 eggs, room temperature; 6 cups powdered sugar, sifted; 1/2 cup unsalted butter, room temperature; 1/2 teaspoon salt; 1/2 teaspoon cinnamon essence (or other choice); fine zest of one Meyer's lemon; 1/2 teaspoon fine zest of orange; 1/2 teaspoon fresh ground fennel seed; 1/4 teaspoon dried lavender flowers, optional; 2 pounds cake flour; old gold luster dust, sold in 2 gr. size; 1 tablespoon cinnamon schnapps or other spirit