Ingredients:

  • 1 standard box (approx. 15.25 oz) Box Cake Mix (Yellow or Chocolate)
  • 1 cup Whole Milk or Buttermilk, room temperature
  • 1/2 cup Melted Unsalted Butter
  • 3 Large Eggs
  • 2 teaspoons Vanilla Extract
  • 1/2 cup Sour Cream or Full-Fat Greek Yogurt
  • 1/2 teaspoon Baking Powder (Optional)
  • 1 teaspoon Instant Espresso Powder (Optional, dissolved in 1 tbsp hot water for chocolate mix)

Instructions:

  1. Preheat oven according to the box directions. Grease and flour the chosen baking pan(s) thoroughly.
  2. If using espresso powder (for chocolate), dissolve it in 1 tablespoon of hot water and set aside to cool slightly.
  3. Empty the box mix into a large bowl and whisk briefly to break up clumps.
  4. Add the melted butter, milk/buttermilk, eggs, sour cream/yogurt, and vanilla extract (and dissolved espresso, if applicable) to the dry ingredients.
  5. Beat on medium speed for exactly 2 minutes, scraping down the sides halfway through. Do not overmix; the batter should be smooth but not elastic.
  6. If concerned about density, gently fold in the optional 1/2 teaspoon of baking powder now.
  7. Pour the batter evenly into the prepared pan(s). Bake according to the package time, checking for doneness 5 minutes before the box suggests.
  8. Test for doneness: A skewer inserted into the centre should come out with moist crumbs attached, but no wet batter.
  9. Cool the cake in the pan on a wire rack for 10–15 minutes before inverting onto the rack to cool completely.