Preheat oven to 400F and line a baking sheet with parchment paper. In a large bowl, whisk together gluten free flour, sugar, baking powder, and salt. Cut in cold butter using a pastry cutter until the mixture resembles coarse crumbs.
Gently fold in blueberries. In a small bowl, whisk together cold heavy cream, egg, vanilla extract, and lemon zest. Pour into the flour mixture and stir until a shaggy dough just comes together.
Turn the dough out onto a surface dusted with gluten free flour and gently pat into a 7-inch round disc about 1 inch thick. Cut into 8 wedges and place on the prepared baking sheet about 2 inches apart.
Bake for 18 to 22 minutes until the tops are golden and the scones are set. Let cool on the baking sheet for 10 minutes.
Whisk together powdered sugar and lemon juice until smooth. Drizzle the glaze over the warm scones and let set for 5 minutes before serving.