Blueberry Sour Cream Swirl

Blueberry Sour Cream Swirl

Ingredients

• 2 cups all-purpose flour

• 1 cup granulated sugar

• 2 tsp baking powder

• 1/2 tsp baking soda

• 1/2 tsp salt

• 1/2 cup (1 stick) unsalted butter, softened

• 2 large eggs

• 1 cup sour cream (full-fat preferred)

• 1 tsp pure vanilla extract

• 1 tbsp lemon zest (optional, brightens flavor)

Blueberry Swirl

• 2 cups fresh or frozen blueberries

• 1/4 cup granulated sugar

• 1 tbsp lemon juice

• 1 tsp cornstarch mixed with 1 tsp cold water (slurry)

• Pinch of salt

Instructions

1. Prep

• Preheat oven to 350°F (175°C). Grease a 9x9-inch baking pan (or line with parchment) and set aside.

1. Make the blueberry filling

• In a small saucepan, combine blueberries, 1/4 cup sugar, lemon juice, and a pinch of salt. Cook over medium heat until the berries begin to break down and release juices, about 5–7 minutes.

• Stir in the cornstarch slurry and cook 1–2 minutes more until slightly thickened. Remove from heat and let cool to warm or room temperature.

1. Make the batter

• In a large bowl, whisk together flour, baking powder, baking soda, and salt.

• In another bowl or stand mixer, cream the softened butter and 1 cup sugar until light and fluffy, about 2–3 minutes.

• Add eggs one at a time, beating well after each. Mix in vanilla and lemon zest.

• Alternately add the flour mixture and sour cream in three parts, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.

1. Assemble and swirl

• Spread about two-thirds of the batter evenly into the prepared pan.

• Spoon the cooled blueberry mixture over the batter in an even layer.

• Drop spoonfuls of the remaining batter over the blueberry layer. Use a butter knife or skewer to gently swirl the top layers together to create a marbled effect—avoid over-swishing.

1. Bake

• Bake for 35–45 minutes, or until the top is golden and a toothpick inserted into the center comes out with a few moist crumbs (not wet batter).

• If the topping is browning too quickly, tent loosely with foil for the last 10–15 minutes.

1. Cool and serve

• Cool in the pan on a wire rack for at least 20–30 minutes before slicing. The bars will firm up as they cool.

• Serve warm or at room temperature. Optionally dust with powdered sugar or top with a simple glaze (1 cup powdered sugar + 1–2 tbsp lemon juice or milk) for extra sweetness.

Storage

• Store in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days. Reheat gently before serving if desired.

Tips

• For an even topping, reserve a few tablespoons of the blueberry sauce to swirl on top after dolloping the remaining batter.

• Use frozen blueberries without thawing if fresh aren’t available; add 1–2 minutes to cooking time for the filling if needed.

• For a lighter texture, substitute half the butter with 1/2 cup neutral oil and reduce sour cream to 3/4 cup; results will be slightly more tender and moist.