BrandNewCake Palette Knife/Glaze Knife 15cm The BrandNewCake Palette Knife/Glaze Knife 15cm is a knife with a plastic handle. The length of the knife is 15 centimetres. This size is perfect for decorating smaller surfaces. Use this product to spread buttercream, icing or ganache on your sponge cake, for example. The knife is not that big, which allows you to work precisely and get a tight result.