Preheat the oven to 450°F
Place the butter in a 9×9-inch baking dish and put it in the oven while it preheats. Allow the butter to melt completely
In a small bowl, toss the blueberries with the sugar and flour
In a large bowl, whisk together the flour, baking powder, salt, and sugar
In a separate bowl, combine the buttermilk, vanilla extract, and melted butter
Pour the wet ingredients into the dry ingredients and stir gently just until combined. DO NOT OVERMIX
Gently fold the blueberries into the dough using minimal mixing
Carefully spread the dough into the hot butter in the baking dish
Use a knife to score the dough into 9 squares before baking
Bake for 30-35 minutes, until the biscuits are deeply golden brown and the center is fully set. Place lined pan underneath to catch potential spillage. Keep your eye out for browning- tent loosely with foil around 25 minutes and then bake another 10 minutes until done
Let the biscuits cool in the pan for about 10 minutes
In a small bowl, whisk together the powdered sugar, cream, vanilla extract, and a pinch of salt until smooth and pourable
Drizzle the glaze lightly over the warm biscuits so it melts slightly into the surface
