When you cut into a cake, give your guests a surprise under the icing. Colouring a cake mix produces a brightly coloured baked cake. Food colouring is the secret to dying your cake mix, and it is available in many more colours today than just red, yellow and blue. Look for speciality food colours at baking supply stores, and add them to a light-coloured cake mix.
Prepare the cake mix according to the package directions.
Add three to five drops of food colouring to the cake mix and stir it in.
Check the colouring for the desired shade and add more food colouring if desired. The cake will bake to a lighter colour than the batter. For instance, if you want a light pink cake, add red colouring to a white cake batter until it turns dark pink. In "The Cake Doctor," the recipe for Quick Red Velvet Cake requires adding an entire bottle of red food colouring to a chocolate cake mix to get a dark red colour instead of pink.
Use a colour mixing chart to create different colours from primary colours. For instance, the chart on Baking 911 recommends using one part each of blue and black to create grey.
Bake the cake as directed.
Light or white cake mixes work best. You will not see the colouring as well if you add it to a dark chocolate cake instead of a white cake.