Step 1: Prepare Pans and Preheat
Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans with butter or cooking spray. Line bottoms with parchment paper rounds, then grease the parchment. Lightly dust with flour or cocoa powder, tapping out excess. Set aside.

Step 2: Mix Dry Ingredients
In a large bowl, whisk together flour, sugar, baking soda, baking powder, salt, and cocoa powder. Whisk thoroughly to combine and remove any lumps. Set aside.

Step 3: Cream Butter and Oil
In the bowl of an electric mixer fitted with paddle attachment (or using a hand mixer), beat the softened butter on medium speed until creamy, about 1 minute. Add the oil and beat until combined and smooth.

Step 4: Add Eggs
Add eggs one at a time, beating well after each addition. Scrape down the sides of the bowl as needed. The mixture should be smooth and fluffy.

Step 5: Mix Wet Ingredients
In a measuring cup or small bowl, combine buttermilk, vanilla extract, vinegar, and food coloring. Stir until food coloring is evenly distributed.

Step 6: Alternate Adding Ingredients
With the mixer on low speed, add the flour mixture in three additions, alternating with the buttermilk mixture in two additions. Begin and end with flour mixture. Mix each addition just until combined – don’t overmix! Scrape down the bowl and give it a final stir by hand to ensure everything is incorporated. The batter will be smooth and deep red (or pink).

Step 7: Divide and Bake
Divide batter evenly between prepared pans (use a kitchen scale for precision – about 550g per pan). Smooth tops with a spatula. Gently tap pans on counter 2-3 times to release air bubbles.

Bake for 28-32 minutes, or until a toothpick inserted in the center comes out clean or with just a few moist crumbs. Don’t overbake! Cakes should spring back when lightly touched.

Step 8: Cool Cakes
Remove from oven and cool in pans on wire racks for 10 minutes. Run a knife around edges, then carefully invert onto wire racks. Peel off parchment paper. Flip cakes right-side up and cool completely before frosting (at least 1 hour).

Step 9: Make Cream Cheese Frosting
In a large bowl using an electric mixer, beat softened cream cheese and butter together on medium speed until smooth and creamy, about 2 minutes. Reduce speed to low and gradually add sifted powdered sugar, one cup at a time. Add vanilla and salt. Increase speed to medium-high and beat for 2-3 minutes until light and fluffy. Don’t overbeat or frosting can become too soft.

Step 10: Assemble and Frost
Level cake tops if domed (use a serrated knife or cake leveler). Place one cake layer on serving plate or cake board. Spread about 1 cup of frosting evenly over the top. Place second layer on top, pressing gently. Apply a thin “crumb coat” of frosting over entire cake to seal in crumbs. Refrigerate 15-20 minutes until firm.

Apply final coat of frosting, smoothing top and sides with offset spatula or bench scraper. Decorate as desired with piped swirls, fresh strawberries, chocolate hearts, or sprinkles.

Step 11: Serve
Refrigerate cake for at least 30 minutes to set frosting before slicing. Remove from fridge 20-30 minutes before serving for best flavor and texture. Slice with a sharp knife, wiping clean between cuts.