Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper. Zest and juice 1 fresh lemon to get 2 tablespoons zest and 2 tablespoons juice.
In a medium bowl, combine 2/3 cup Greek yogurt, 2 tablespoons milk, 1 egg, 2 teaspoons vanilla extract, 1/4 cup cane sugar, 2 tablespoons fresh lemon juice, 2 tablespoons lemon zest, and 2 tablespoons maple syrup. Whisk until completely smooth.
In a large bowl, whisk together 1-1/3 cups oat flour, 2/3 cup gluten-free flour, 1-1/4 teaspoons baking powder, 1/4 teaspoon baking soda, and 1/2 teaspoon salt until well blended.
Remove 1/2 cup butter from the fridge and immediately slice it into small pieces. Add to the flour mixture and use a pastry cutter or your hands to work it in until the mixture is crumbly with small chunks of butter throughout.
Pour the wet mixture into the flour mixture and stir with a spatula until all the flour is incorporated. The dough will be fluffy and slightly sticky. Gently fold in 1 cup fresh blueberries.
Dump the dough onto a floured cutting board and shape into a large disc about 1 inch tall. Using a sharp knife, slice into 8 wedges and place them 1 inch apart on your prepared baking sheet. Optional: sprinkle the tops with turbinado sugar for extra crunch.
Bake for 20-22 minutes or until lightly golden brown. While they cool, whisk together 1/4 cup Greek yogurt and 2 tablespoons maple syrup for the glaze, adding a little milk if needed for drizzling consistency. Drizzle over cooled scones.