Easy confetti cake or funfetti cake recipe from scratch, homemade with simple ingredients. this soft and moist birthday cake is paired with fluffy vanilla buttercream frosting and rainbow sprinkles. sprinkles make everything feel special and more festive this is the easiest cake to make from scratch for your next celebration of any kind. this rainbow sprinkle cake or these birthday sprinkle cookies {with cake mix} are also great options. how to make easy homemade funfetti cake recipe from scratch? cream butter and sugar-until fluffy. add other ingredients-this includes eggs, egg whites, vanilla extract, almond extract. mix-until combined. whisk dry.