Buttermilk is magic. It turns everything into gold: super-moist, super-delicious gold.
This cake is a long-time family favorite. My mother made it for my siblings and me when we were young, and every time I pull it out of the oven, clichè as it sounds, I am reminded of summer mornings in my childhood kitchen. It’s simple, adaptable, and make aheadable 🙂
½ cup (8 tablespoons | 4 oz | 113 g ) unsalted butter, room temperature
zest from 1 large lemon
1 cup (214 g) sugar (set aside 1 tablespoon for sprinkling)
1 egg, room temperature
1 tsp. vanilla
2 cups (256 g) all-purpose flour (set aside 1/4 cup of this to toss with the blueberries)
2 tsp. baking powder
1 tsp. kosher salt (I like 1.25 tsp)
2 cups fresh blueberries, picked over
½ cup buttermilk
Preheat the oven to 350ºF. Using a stand mixer or hand-held mixer, cream the butter with the lemon zest and the 1 cup minus 1 tablespoon of sugar until light and fluffy.
Add the egg and vanilla and beat until combined. Meanwhile, toss the blueberries with ¼ cup of flour, then whisk together the remaining flour, baking powder and salt.
Add half of the flour mixture to the batter, and stir with spatula to incorporate. Add all of the buttermilk. Stir. Add remaining flour, and stir until flour is absorbed. Fold in the blueberries. (Leave excess flour from the blueberry bowl behind.)
Grease an 8- or 9-inch square baking pan (or something similar—I prefer this 8-inch pan because I like the thicker pieces) with butter or coat with non-stick spray. If you have parchment paper on hand, line the pan with parchment on top of the butter. Spread the batter into the pan. Sprinkle the batter with the remaining tablespoon of sugar. Bake for 35 to 45 minutes — a 9-inch pan will be done in closer to 35 minutes; an 8-inch pan usually needs 40 to 45 minutes. Check with a toothpick for doneness. If necessary, return pan to oven for a couple of more minutes. (Note: Baking for as long as 10 minutes more might be necessary, especially if you’re using a smaller pan such as an 8×8-inch.) Let cool at least 15 minutes before serving.
Can this be made ahead of time? Yes. Prepare the batter, spread it into the prepared baking pan, cover it with plastic wrap, and store in the fridge. In the morning, if time permits, bring it to room temperature for 30 minutes. Sprinkle with the sugar, then bake as directed. It may need more time if the batter was refrigerated.
Can this be doubled? Yes. Bake it in a 9×13-inch pan … like this pan from Pyrex. Increase the baking time but begin checking at the 35 minute mark.
What if I don’t have buttermilk? Use 2% or whole milk or make your own buttermilk: place 2 teaspoons of vinegar or lemon juice in a liquid measuring cup. Fill cup with milk until it reaches the 1/2-cup line. Let stand for five minutes. Use as directed.
Can this be made gluten free? Yes. I like Cup4Cup and King Arthur Flour gluten-free flour mixes, but use whatever you like, keeping in mind that all gluten-free flours absorb liquid differently, so you may need to adjust to get the batter to the right consistency.
Should the batter be thick? Yes. As with all baking, I highly recommend using a scale to measure the flour. I have this one, which costs under $11.
Can I bake this into muffins? Yes. Follow the baking directions on this post.