Step 1

Preheat the oven to 375 degrees F (190 degrees C). Butter and lightly flour the sides of a 9-inch springform pan and line the bottom with parchment paper.

Step 2

Place blueberries in a bowl and toss with 1 tablespoon flour and 1 teaspoon lemon juice.

Step 3

Beat eggs and sugar in a mixing bowl using an electric mixer on high speed until thickened and light in color, at least 5 minutes. Mix in sour cream, vegetable oil, vanilla extract, and salt on low speed until just combined. Add 2 cups flour and baking powder and mix until combined. Add lemon juice and lemon zest and mix well.

Step 4

Pour 1/2 the batter into the prepared pan and spread evenly. Spread 1/2 the blueberry mixture over batter. Pour in remaining cake batter and spread remaining blueberries on top, pushing them halfway into the batter.

Step 5

Bake in the preheated oven until top is browned and a toothpick inserted into the center comes out clean, 35 to 45 minutes. Remove outer ring from springform pan and let cool completely. Dust top of cooked cake with confectioners' sugar using a small sifter.