Prepare the Berries: In a medium bowl, gently toss the berries with the sugar. Let the berries macerate while the cake is made.
Make the Cake: Preheat oven to 350 degrees F. Butter a 9-inch springform pan; set aside.
Add the cake ingredients to a food processor in the following order, pulsing briefly after each addition: sugar, egg yolks, ricotta, mascarpone, flour, baking powder, orange zest, Grand Marnier and salt. After all of the ingredients have been added, blend until smooth, about 20 seconds. Transfer to a mixing bowl and set aside.
Using an electric mixer, beat the egg whites until just short of stiff peaks. Gently fold the egg whites into the batter.
Pour the batter into the prepared springform pan. Bake until the center of the cake springs back when touched and appears just set, 45 to 50 minutes. Allow to cool slightly before releasing the sides of the pan.
Allow to cool to room temperature. When ready to serve, drain the berries in a colander. Serve at room temperature topped with the berries. The cake is best served shortly after making, although you can keep it at room temperature or chilled for up to one day, but only top with the berries just before serving.