Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round pan, preferably one that's at least 2 inches high (or line with parchment).
Mix dry ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
Cream butter and sugar: In a large bowl, beat the butter, sugar, and lemon zest together until very light and fluffy (about 3–4 minutes).
Add eggs and vanilla: Beat in the eggs one at a time, then add the vanilla extract.
Mix in sour cream: Mix in the lemon juice and sour cream until well combined. It may look slightly curdled — that’s fine!
Combine: Add the dry ingredients to the wet ingredients and gently mix just until combined. Pour in the buttermilk and give it a last mix. Don't overmix.
Prepare blueberries: Toss 1¾ cups of the blueberries (keep the rest for later) with 1 tablespoon flour. Gently fold the coated blueberries into the batter.
Assemble: Spread the batter into the pan. Scatter the remaining 1 cup of blueberries evenly over the top. (If desired, sprinkle coarse sugar over the batter for a beautiful crunchy topping).
Bake: Bake for about 40-45 minutes, or until the top is golden, the cake is high, and a toothpick inserted into the center comes out with a few moist crumbs. Tip: If the cake starts browning too much on top before it's fully baked, loosely cover it with foil.
Cool: Cool in the pan for 15 minutes, then transfer to a wire rack to cool completely.
Dust with powdered sugar.
Video
Notes
Pan Size: Use a 9-inch (23cm) round pan that’s at least 2 inches deep. An 8-inch pan works too but may require 5–10 extra minutes of baking time.
Sour Cream: Adds moisture and richness with a slight tang. You can substitute with whole milk Greek yogurt for a lighter version.
Buttermilk: Keeps the cake tender and soft. Regular milk works, but buttermilk gives better texture.
Blueberries: Fresh blueberries give the best texture and color. Frozen work too—don’t thaw them before using to avoid bleeding.
Storage: Store covered at room temp for 1 day or refrigerate for up to 4 days. Best enjoyed fresh or slightly warmed.
Watch the Video: Want to see the texture and steps? Watch the full video tutorial for best results.
Tip: Tossing blueberries in flour helps prevent them from sinking.