Preheat Oven & Prepare Pan: Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.
Mix Dry Ingredients: In a large bowl, whisk together flour, sugar, baking powder, and salt.
Add Wet Ingredients: Pour in buttermilk and stir until just combined. The dough should be slightly sticky.
Fold in Blueberries: Gently fold in fresh blueberries, being careful not to crush them.
Shape Biscuits: Use a spoon or cookie scoop to drop biscuit dough onto the baking sheet. Space them about 2 inches apart.
Add Butter Swim: Pour melted butter evenly over the top of the biscuits.
Bake: Bake for 30 minutes, until golden brown and a toothpick comes out clean.
Prepare Glaze: In a small bowl, whisk together powdered sugar, lemon juice, and vanilla until smooth.
Glaze Biscuits: Drizzle glaze over warm biscuits. Serve immediately for best texture and flavor.