This shortcake can be made as a scone — round and served warm with butter — but I decided to do it in a star shape because it is more fun as a Fourth of July dessert, served with fresh raspberries and whipped cream. These are delicious and very festive.
Position an oven rack in the center of the oven and preheat the oven to 400 degrees. Line a large rimmed baking sheet with parchment paper or a silicone baking mat.
In a large bowl, whisk together the flour, the ¼ cup sugar, baking powder, salt, and lemon zest. Using a pastry blender or your fingertips, work in the butter until the mixture is crumbly with some pea-sized pieces of butter. Add the 1 cup of heavy cream and stir just until the dry ingredients are moistened and combined. Do not overmix.
On a lightly floured work surface, roll out the dough into a 1-inch-thick rectangle. Spread the blueberries evenly on top of dough. Gently work the dough into a ball, being careful not to crush the berries, and roll the dough out again into a 1-inch-thick rectangle.
Using a 3-inch star cookie or biscuit cutter dipped in flour, cut out the shortcakes, cutting them as close together as possible to avoid excess scraps. Arrange the shortcakes about 3 inches apart on the prepared baking sheet. Gently press the scraps together, roll out again, and cut more stars. Using a pastry brush, lightly brush the tops of the shortcakes with the remaining 2 teaspoons cream and sprinkle with the remaining 1 teaspoon sugar.
Bake until the shortcakes are golden brown and feel somewhat firm when the tops are pressed with a fingertip, 25 to 30 minutes. Serve warm, or let cool to room temperature.