Step 1

Preheat the oven to 350 degrees.

Step 2

Grease and flour a 9-inch round springform pan, shaking out any excess flour.

Step 3

Place the butter and sugar in

Step 4

the bowl of an electric mixer fitted with the paddle attachment and beat on

Step 5

medium speed for 3 minutes, until light and fluffy, scraping down the sides of

Step 6

the bowl as needed. With the mixer on low, add the eggs one at a time, mixing

Step 7

well after each addition. Add the ricotta, sour cream, vanilla, and lemon zest

Step 8

and mix well. (The batter will look curdled.)

Step 9

In a small bowl, stir together

Step 10

the flour, baking powder, and 1 teaspoon salt. With the mixer on low, slowly

Step 11

add the dry ingredients to the batter, mixing just until incorporated. With a

Step 12

rubber spatula, fold two thirds of the blueberries into the batter. Transfer

Step 13

the batter to the prepared springform pan and smooth the top. Scatter the

Step 14

remaining blueberries on the cake, pressing them lightly into the surface.

Step 15

Bake for 45 to 55 minutes, until

Step 16

a toothpick inserted in the center comes out clean. Transfer to a wire rack and

Step 17

allow to cool in the pan for 15 minutes. Remove the sides of the pan and

Step 18

lightly dust the top with the confectioners’ sugar. Serve warm or at room

Step 19

temperature.