Heat the oven to 425 degrees. Line a baking sheet with parchment paper.
Combine the flour, 1/4 cup sugar, baking powder, and baking soda in a medium bowl. Cut in the butter with a pastry blender until the butter is the size of large blueberries. Stir in the sour cream and milk until a dough forms.
On a lightly floured surface, pat the dough to 3/4-inch thickness. Using a 3-inch round, cut the dough into 6 shortcakes, pressing the dough scraps together as necessary.
Place on a baking sheet; sprinkle with additional sugar if desired. Bake for 12 to 15 minutes or until golden brown.
Meanwhile, process the cottage cheese, 1 tablespoon sugar, and vanilla in food processor until smooth. Add the whipping cream; process until lightly whipped.
Combine the blueberries and preserves in a medium microwave-safe bowl. Microwave on high for 30 seconds or until the preserves are melted.
Split the shortcakes, layer with the blueberries and the cream mixture.