How to Make It
Prepare the Biscuits: Preheat oven to 400°F. Stir together flour, granulated sugar, baking powder, and salt in a large bowl. Using your hands or a pastry blender, gently combine flour mixture and butter until mixture resembles small peas. Stir in vanilla and 1 cup and 3 tablespoons of the heavy cream. (Mixture will be crumbly.) Turn out dough carefully onto a lightly floured surface, and gently pat into 1-inch-thick disk. Using a 2 1/2-inch round cutter, cut 8 Biscuits, gathering and patting scraps as needed.
Transfer Biscuits to a baking sheet lined with parchment paper or a silicone baking mat. Brush tops lightly with remaining 1 tablespoon heavy cream, and sprinkle with turbinado sugar. Bake in preheated oven until golden and resistant to the touch, 20 to 25 minutes. Cool on a wire rack about 30 minutes.
Meanwhile, prepare Filling: Beat whipping cream with an electric mixer with chilled beaters on high speed in a large chilled bowl until stiff peaks form, about 4 minutes. Using a rubber spatula, gently fold in lemon curd, and if desired, Grand Marnier.
Split Biscuits, and place on a serving platter. Serve with Lemon Cream Filling and fresh fruit.
Shortcake Cream Biscuits can be made up to 2 days ahead; store in an airtight container at room temperature. Lemon Cream Filling can be made up to 4 hours ahead; cover and store in refrigerator.