Directions

1. Preheat oven to 350F. Grease the bottom of three 9-inch cake rounds and line each with round parchment paper. Set aside.

2. Whisk together flour, baking powder, baking soda, and salt and set aside.

3. Using a hand or stand mixer, cream together the butter and sugar for 3-5 minutes, or until light and fluffy. Add oil and mix on low to incorporate. 

4. Mix in eggs one at a time on medium speed. Add vanilla and sour cream. 

5. Begin adding buttermilk and dry ingredients to the batter, alternating between buttermilk and dry ingredients. (dry, wet, dry, wet, dry).

6. Add sprinkles and fold into batter with a spatula.

7. Pour cake batter evenly between three lined cake tins. Bake 30-35 minutes, or until toothpick inserted into center of cakes comes out clean.

8. Remove cake tins from oven and let cakes cool in tins for 30 minutes, before removing and placing on cooling rack to cool completely.

9. If frosting the cake that day, transfer cakes from cooling rack to the fridge to cool completely before assembling. If baking the day before, allow cakes to cool to room temperature before wrapping in plastic wrap and storing in the refrigerator overnight. 

10. Prepare buttercream: cream together butter and tahini until smooth and creamy. Begin to add one cup of powdered sugar at a time, adding the milk and vanilla as it begins to thicken. If the buttercream becomes too thick, add in another tablespoon of milk.

11. Assemble the cake: place one layer of the cake on cake stand or serving plate. Add a thin layer of buttercream and repeat with remaining cake layers. Spread buttercream over cake and decorate with sprinkles. Enjoy!