Preheat the oven to 400ºF and line a large baking sheet with parchment paper or a silicone baking mat.
Whisk oat flour, sugar, cornstarch, baking powder, baking soda, and salt together in a large bowl.
Add the ricotta cheese and use a spatula or large spoon to gently mix it in. Press the back of your spatula (or spoon) against any large lumps to break them up. You don’t need it perfectly smooth—just mix until the dough looks mostly uniform with a few small ricotta bits throughout.
In a small bowl, whisk the egg, olive oil, and vanilla extract together.
Pour the wet mixture into the dry mix and use a spatula to combine everything. The mixture will seem dry at first, but keep mixing, making sure to scrape the bottom of the bowl. Fold in the blueberries or mix-in of choice.
Using your hands, form the dough into a ball. If the mixture is too dry, add an extra tablespoon of olive oil, and if it's too wet, add a little extra oat flour.
Turn the dough out onto a lightly floured surface. Shape into an 8-inch circle, then cut into 8 wedges using a sharp knife or bench scraper.
Arrange the scones a couple of inches apart on the prepared baking sheet. Brush the scones with your milk of choice and sprinkle with turbinado sugar (optional). Bake for 15-17 minutes or until lightly golden around the edges.
Allow the scones to cool before proceeding with optional glaze. See the post above for variation and topping ideas.