Step 1

Preheat an oven to 375°F (190°C). Generously coat an 8-inch (20-cm) round cake pan with nonstick cooking spray.

Step 2

In the bowl of an electric mixer fitted with the whisk attachment, combine the eggs and the 1/2 cup (4 oz./125 g) granulated sugar. Beat on medium speed until the mixture thickens and turns a shade paler, 4 to 5 minutes. Reduce the mixer speed to low, then add the ricotta, sour cream, butter, lemon zest and vanilla and almond extracts. Beat until combined, about 30 seconds. Add the flour, baking powder and salt and beat until just combined, about 15 seconds. Increase the mixer speed to medium-high and beat for 1 minute more.

Step 3

Pour the batter into the prepared pan and spread evenly. Top the batter with 1 1/2 cups (6 oz./185 g) of the blueberries, concentrating them in the center of the cake.

Step 4

Bake until the edges of the cake are golden brown, about 40 minutes. The cake should be set but still jiggle slightly in the center. Transfer to a wire rack and let cool for 20 minutes.

Step 5

Meanwhile, in a small bowl, toss the remaining 1/2 cup (2 oz./60 g) blueberries with the lemon juice and the remaining 1 tsp. sugar. Set aside.

Step 6

To make the mascarpone whipped cream, in the bowl of an electric mixer fitted with the whisk attachment, beat the cream on medium speed until soft peaks form, 1 to 2 minutes. Add the mascarpone cheese, granulated sugar and vanilla and beat until medium peaks form, about 10 seconds.

Step 7

To serve, pile the sugared blueberries in the center of the cake. Lightly dust the edges of the cake with confectioners’ sugar. Cut the cake into wedges and serve with the mascarpone whipped cream alongside. Serves 6 to 8.

Step 8

Williams Sonoma Test Kitchen