Ingredients : 

• ½ cup (113 g) unsalted butter softened to room temperature.
• ½ cup (120 g) avocado, canola or vegetable oil.
• 1 ½ cup (300 g) granulated sugar.
• 4 large eggs room temperature preferred.
• 1 tablespoon baking powder.
• ½ tablespoon salt.
• 1 tablespoon vanilla extract.
• 3 cups (375 g) all-purpose flour.
• 1 ¼ cup (300 ml) buttermilk room temperature preferred.
• 1 batch chocolate frosting click link for recipe, or use one of the other frosting recommended in the notes below.

Instructions : 

1. Prepare the Oven and Pans:

   Preheat the oven to 350°F (177°C). Line the bottoms of two deep 8-inch round cake pans with parchment paper, and lightly grease the sides to prevent sticking. Set the pans aside.

2. Cream Butter, Oil, and Sugar:

   In the bowl of a stand mixer (or using a hand mixer), cream together ½ cup (113 g) unsalted butter, ½ cup (120 g) canola or vegetable oil, and 1½ cups (300 g) granulated sugar until the mixture is light and creamy.

3. Add Eggs and Vanilla:

   Add 4 eggs, one at a time, beating well after each addition. Stir in 1 tablespoon vanilla extract.

4. Mix Dry Ingredients:

   In a medium bowl, whisk together:
   • 3 cups (375 g) all-purpose flour
   • 1 tablespoon baking powder
   • ½ teaspoon salt

5. Combine Wet and Dry Ingredients with Buttermilk:
   

   Using a spatula, alternate adding the dry flour mixture and 1¼ cups (300 ml) buttermilk to the butter mixture. Begin and end with the flour mixture. Gently hand-mix until just combined, do not over-mix to keep the batter light. Small lumps are okay, and avoid using a mixer at this stage.

6. Divide and Bake:
   

   Evenly divide the batter between the prepared pans. Bake for 30-35 minutes, or until the cake springs back when lightly touched and a toothpick inserted in the center comes out with a few moist crumbs (no wet batter).

7. Cool the Cakes:
   

   Let the cakes cool in their pans for 10-15 minutes. Then invert them onto a cooling rack, remove the parchment paper, and let them cool completely before frosting.

8. Frost and Decorate:
   

   Frost the cake using your favorite chocolate frosting (or another frosting of choice). Decorate with sprinkles or other toppings as desired.