Preheat the oven to 400°F. Line a large baking sheet with parchment paper. Place the butter in the freezer for 10–15 minutes so it gets extra cold.
In a large bowl, mix together the gluten-free flour, xanthan gum, salt, baking powder, and unrefined cane sugar.
In a smaller bowl, whisk the egg. Add the blended cottage cheese, lemon juice, and lemon zest, and mix until combined.
Add the wet mixture to the dry ingredients and mix gently until just combined. The dough will still be a bit crumbly. That's ok. We want to keep it that way before the next step.
Take the butter out of the freezer and grate it into the dough, kneading lightly as you go so it disperses evenly. If the dough is too dry, add a little more lemon juice.
Using wet hands, form the dough into a ball and transfer it to a generously floured surface. Knead in additional flour as needed and roll into a 7-inch circle. Cut into 8 triangles and carefully transfer to the prepared baking sheet.
Prepare the egg wash by whisking the egg with water. Brush the tops of the scones with the egg wash. You will only end up using about 1 tbsp of egg wash in total.
Bake for 18–20 minutes, until lightly golden. Remove from the oven and let the scones cool on the baking sheet.
Optional: Mix the lemon juice with powdered sugar to make the glaze and drizzle over the scones before serving.