Preheat oven to 350 degrees F. Prepare two 8-inch cake pans by lining them with parchment paper.

Using stand mixer or large bowl, combine butter and sugar and beat together for 2 minutes. Add oat milk, lemon juice, vanilla extract and lemon zest and whisk until combined.

In small bowl, sift together flour and baking powder into wet ingredients and add salt. Mix until well combined. Stir in sprinkles.

Evenly distribute cake mix into both cake pans and bake for 30 minutes, or until toothpick comes out clean.

Remove cake from oven and allow to cool completely before frosting.

Add frosting to top layer of one cake in an even layer and add the other cake on top. Frost entire cake with remaining frosting and add sprinkles as desired.