Step 1

Preheat oven to 350F. Combine 2 cups milk with vinegar and set aside to sour.

Step 2

Grease three 8-inch pans or four 6-inch pans and line the bottom with a parchment paper circle, cut to fit the pan, and then grease the parchment paper circle. I don’t recommend skipping this step or your cakes could stick to the bottom of the pan. Set pans aside. Alternatively, you can line a cupcake pan with paper liners.

Step 3

In a large bowl, mix together dry ingredients—flour(s), sugar, baking soda, baking powder, & salt until well combined.

Step 4

Mix in oil, vanilla, and sour milk with a whisk or mixer and beat just until blended and smooth. Don’t over-beat.

Step 5

Evenly distribute the cake batter into the three pans and place onto the middle rack in the preheated oven. Bake for 20-30 minutes, or until center is set and a toothpick inserted comes out with a few moist crumbs. Cake/cupcakes will be pretty light in color. More or less time may be needed depending on your oven.

Step 6

Let cakes cool for several minutes in the pan before inverting onto a cooling rack to cool thoroughly. Cakes are the easiest to frost when they are wrapped in plastic wrap and frozen overnight.

Step 7

To decorate, place on cake layer upside down on a decorative stand or plate. To keep the plate clean, you can tuck strips of parchment paper under the cake to catch the frosting. Place a dollop of chocolate frosting on the first layer and spread across evenly using an offset spatula. Repeat with remaining layers and frost the top and sides of the cake

Step 8

I piped a reverse shell border with the remaining frosting using a piping bag and a Wilton 1M tip, but a border isn’t necessary if you don’t have the materials.

Step 9

Sprinkle the top of the cake with colorful sprinkles.