Preheat oven to 450F degrees (yes, that is the correct temperature). Spray a 9x9-inch baking dish with nonstick cooking spray.
In a microwave-safe bowl melt 1/2 cup (1 stick) unsalted butter in the microwave. Pour melted butter into prepared baking dish. Note: you can melt the butter directly in the dish as long as it's not metal.
In a medium bowl, mix together 2 1/2 cups all-purpose flour, 1/4 cup granulated sugar, 1 Tablespoon aluminum-free baking powder and 1/2 teaspoon salt.
Pour in 1 3/4 cups buttermilk. Stir until a sticky dough forms. If batter still looks dry, add a tad bit more of the buttermilk until you have a sticky dough.
Gently stir in 1 1/2 cups blueberries.
Pour biscuit dough into baking dish (right on top of the melted butter.) Some of the butter will run over the top of the dough. Spread out the batter evenly (as best as you can). I find this is easiest if I spray my hand with nonstick spray and then gently push the batter around.
Cut the dough into 9 squares. This doesn’t need to be perfect. It will just help with cutting the finished biscuits later.
Bake (on the middle oven rack) for about 25-30 minutes, rotating dish once during baking. Tops should be golden brown and when you insert a toothpick in the center, it should come out clean with no wet batter.
In a bowl, whisk together 1 cup powdered sugar and 2-3 Tablespoons milk. Drizzle on top of the warm biscuits.
Allow the biscuits to cool slightly then slice and serve.
Video
Notes
Please refer to my FAQ’s and ingredient list above for other substitutions or for the answers to the most common questions.
Please note, oven times do vary. The factor depends on many things like if you have an electric, gas or convection oven. It also changes depending if you use a metal pan (not recommended) versus ceramic or Pyrex. It also varies depending on which oven rack you use. A toothpick inserted should not have any wet batter on it. Start with the lowest baking time and go up from there. Use your best judgement based on your own personal knowledge of your particular oven.
I don't recommend a metal baking dish for these. The outside can get overdone before the middle is ready. An oven-safe glass or ceramic dish works best.
Fresh or frozen blueberries can be used. If using frozen, thaw them first then pat dry with paper towels so they don't add additional moisture to the dough.