Use gel food coloring for vibrant red without thinning the batter, and adjust the amount based on brand strength. If buttermilk is unavailable, make a substitute by mixing 1 1/4 cups milk with 1 tablespoon vinegar and resting for 5 minutes. Chilling the frosted cake before adding ganache prevents melting and creates clean drips, while cooling the ganache until it ribbons off a spoon ensures the right viscosity. For extra moisture, brush layers lightly with simple syrup before frosting. Keep cream cheese and butter just soft, not melty, for stable frosting, and store the cake covered in the fridge for up to 4 days, allowing slices to come to room temperature before serving.