Step 1
Preheat oven to 350°F. Grease and line one half sheet baking pan with parchment paper.
Step 2
In a large bowl, at medium speed, beat together butter and sugar until light and fluffy. Add the eggs, one at a time, and the vanilla. Continue mixing until well incorporated. Scrape the bowl as needed.
Step 3
In a separate bowl, whisk flour, baking powder, and salt. With the mixer at low speed, alternately add flour mixture and milk. Ending the process with flour mixture. Mix about 1 minute. Add sour cream and mix until incorporated.
Step 4
Fold in rainbow sprinkles. Pour the batter evenly into the prepared baking sheet and bake for 25-30 minutes or until a toothpick inserted in the middle of the cake comes out clean. Do not turn off the oven just yet.
Step 5
Remove the cake from the oven and cool in a wire rack. Crumble the cake into a large bowl.
Step 6
Line one baking sheet with parchment paper and add 2 cups of cake crumbles to it. Distribute evenly and bake for 20 minutes or until golden brown. Remove from oven and cool completely. Once cooled, process in a food processor until the cake crumbles resemble sand. Pour mixture in a shallow dish and set aside.
Step 7
Mix milk and vanilla and combine with the cake crumbles. Toss and mix until the texture of the mixture is compactable enough to form a ball. You may add additional milk if needed.
Step 8
Mix melted chocolate with oil.
Step 9
Using a small ice cream scoop, form balls. Roll each ball between the palms of your hands. Shape until smooth and round.
Step 10
Using disposable gloves, put 1 tablespoon of melted white chocolate in the palm of your hand. Roll a ball of cake and drop into the shallow bowl containing the crumbles sand. Roll each ball until completely coated with the mixture. Place in mini cupcake liners and serve.
Be creative! Cover the balls completely with melted chocolate or drizzle. Decorate with sprinkles.