Preheat the oven to 350°F. Have all ingredients at room temperature, about 70°F. Spray two 9 × 2-inch or 8 × 2-inch round cake pans with cooking spray. For extra insurance, line the bottoms with parchment paper.
Whisk together until thoroughly blended: 2 1/3 cups sifted cake or all-purpose flour 1 1/2 teaspoons baking powder 1/2 teaspoon baking soda 1/4 teaspoon salt Beat in a large bowl until creamy 3/4 cup (1 1/2 sticks) unsalted butter Gradually add and beat on high speed until light and fluffy, 3 to 5 minutes: 1 1/3 cups sugar Beat in, one at a time, until each egg is fully incorporated, scraping down the sides of the bowl as needed: 3 large eggs Beat in: 1 teaspoon vanilla Beating at low speed, add the flour mixture in 3 parts, alternating with: 1 cup buttermilk in 2 parts, beating until smooth and scraping the sides of the bowl as necessary. Divide the batter between the pans and spread evenly.
Bake until a toothpick inserted into the center comes out clean, 25 to 30 minutes in 9-inch pans, 30 to 35 minutes in 8-inch pans. Cool the cakes in the pans on a rack for about 10 minutes before removing the cakes from the pans to cool completely.
Frost with your icing or frosting recipe of choice, or use the recipe below. To make the cake as shown above, divide the frosting, using half between the cake layers and half on top of the cake. Refrigerate to firm up the frosting. Meanwhile, toast on a baking sheet in a preheated 325˚F oven until nicely browned, about 5 to 8 minutes: 2 cups unsweetened flaked coconut Allow the toasted coconut to cool completely before piling it on top of the cake. Store the cake, covered, in the refrigerator.