Ingredients
Method
- Preheat oven to 425°F (220°C) and line or grease a jumbo 6-cup muffin tin. Whisk together the 2 eggs, 1 cup sour cream, ½ cup whole milk, ⅓ cup vegetable oil, and 1 tsp vanilla extract until smooth and uniform, about 1 minute.
- Add the full box of cake mix and fold with a spatula in 15 to 20 slow strokes until no dry streaks remain. Stop while the batter still looks a little lumpy.
- Fold in the 1 cup blueberries with 3 to 4 turns of the spatula.
- Divide batter among the 6 cups, filling each to the very top. Sprinkle ½ tsp coarse sugar over each muffin.
- Bake at 425°F (220°C) for 5 minutes, then reduce heat to 375°F (190°C) and bake for another 18 to 22 minutes until deep golden and a toothpick comes out with just a few moist crumbs. Rest in the tin for 5 minutes, then transfer to a wire rack and serve warm, domed side up.
Notes
Do not swap the jumbo tin for a standard one without adjusting the bake time, as standard cups will under-bake the centers if you follow the same timing. The batter can be made the night before and refrigerated, covered, which often improves the dome since the cold batter takes longer to set on the outside and the center has time to rise more before the crust forms. If your berries sink to the bottom, toss them in 1 tsp of the dry cake mix powder before folding them in.