For the garnishing, you could use gems, which are brightly colored, sugary candies, to create a colorful and playful look. You could sprinkle the gems on top of the cake, creating a sparkling and vibrant layer of sweetness. Alternatively, you could also use gems to create a border around the base of the cake, adding a fun and playful touch. You could also add a few cherry halves or cherry compote on top of the gems for an additional pop of flavor and color. Overall, the gems topping can make for a visually stunning and tasty twist on the classic Black Forest Cake.