Preheat your oven to 450°F (232°C). Line a baking sheet with parchment paper. 2. In a mixing bowl, whisk together the gluten-free flour, xanthan gum (if using), baking powder, and salt. 3. Add the warm water and olive oil. Stir with a fork until a dough forms. It will be slightly sticky. 4. Turn the dough onto a lightly floured surface (use more gluten-free flour). Knead gently 2-3 times, then shape into a ball. 5. Place the dough on the prepared baking sheet. Using your hands or a rolling pin, press or roll it into a 10-inch round, about 1/4-inch thick. 6. Brush the top of the crust lightly with olive oil. Bake for 5 minutes. 7. Remove from oven. Spread pizza sauce evenly over the crust, leaving a small border. Sprinkle with cheese and add toppings. 8. Return to oven and bake for another 5-7 minutes, until cheese is melted and bubbly and edges are golden. 9. Let cool for 2 minutes, then slice and serve.