Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper. This prevents sticking and helps the scones brown evenly.
Mix the dry ingredients: In a large bowl, whisk 2 1/2 cups almond flour, 2 tablespoons tapioca starch (optional), 2 teaspoons baking powder, 1/4 teaspoon fine sea salt, and 1/4 cup granulated sweetener.
Cut in the fat: Add 6 tablespoons cold, cubed butter (or firm coconut oil).
Use a pastry cutter or your fingertips to work it into the flour until the mixture looks like coarse crumbs with some pea-sized bits.
Combine wet ingredients: In a small bowl, whisk 2 large eggs, 1 teaspoon vanilla extract, 1–2 teaspoons lemon zest, and 2–3 tablespoons milk. Start with 2 tablespoons; you can add more if the dough feels dry.
Bring the dough together: Pour the wet ingredients into the dry and stir with a spatula until a thick, slightly sticky dough forms. If it’s crumbly, add 1 more tablespoon milk.
Fold in blueberries: Gently fold in 3/4 to 1 cup blueberries.
If using frozen, do not thaw. Toss them in a teaspoon of tapioca or almond flour first to help prevent bleeding.
Shape the scones: Lightly dust the parchment with almond flour. Pat the dough into a 7–8 inch round, about 1 inch thick.
Use a sharp knife or bench scraper to cut into 8 wedges. Separate the wedges slightly so there’s space between them.
Top and chill briefly (optional): Brush the tops with a little milk and sprinkle with coarse sugar. For cleaner edges, chill the tray in the freezer for 10 minutes before baking.
Bake: Bake 18–24 minutes, until golden on the edges and the centers feel set.
The tops should spring back lightly when touched.
Cool and glaze: Let the scones cool on the tray for 10 minutes, then transfer to a rack. If glazing, whisk 1/2 cup powdered sugar with 1–2 teaspoons lemon juice or milk until smooth and drizzle over warm scones.