To make an easy three-ingredient lemon cake, you’ll need a 16-ounce box of angel food cake mix, a 21-ounce can of lemon pie filling (or lemon curd), and one large lemon.
Use both the lemon juice and zest to add extra, fresh lemon flavor. Additionally, disregard any instructions on the angel food cake mix (such as adding water) and only add the mix.
You'll know the cake is done when the edges are golden brown and a toothpick or knife comes out clean. The result is a light and fluffy cake, full of bright lemon-y flavor.