Preheat oven to 425°F (220°C). Line a rimmed baking sheet with parchment paper.
Freeze butter for about 10 minutes.
In a large bowl, stir together flours, sugar, baking powder, salt, garlic powder, and baking soda. Add cold butter, tossing to coat. Using a pastry blender or 2 forks, cut in cold butter until mixture is crumbly and largest butter pieces are pea-size. (See Notes.) Stir in cheese, green onion, and dill. Using a fork or your fingers, stir in cold buttermilk until a dough forms. (It is OK if there are some dry flour bits remaining.)
Turn out dough onto a clean surface. Pat or roll dough into an 8-inch square (about ¾ inch thick). Using a sharp chef’s knife coated in flour, cut dough in half. Stack halves on top of each other, and pat down into a square. Repeat procedure twice, making sure to press back into an 8-inch square. Using a chef’s knife coated in flour, trim edges, if desired, to create a 7½-inch square, and cut dough into 2½-inch squares. Place 2 inches apart on prepared pan. (See Notes.) Freeze until cold, about 10 minutes.
Brush tops with melted butter.
Bake until golden brown, 12 to 16 minutes. Brush with melted butter, and serve warm.
Notes
Notes:A food processor can be used to cut butter into the dry ingredients. Place dry ingredients into the work bowl of the food processor, and pulse until combined. Add cold butter, and pulse until mixture is crumbly and the largest butter pieces are pea-size. Transfer to a large bowl before adding mix-ins and buttermilk.
Biscuits can be baked touching if you want a softer biscuit. If you like a biscuit with crispy edges, bake about 2 inches apart. Biscuits that are touching will take longer to bake, and biscuits with space between them will bake faster.
Recipe by Bake from Scratch at https://staging.bakefromscratch.com/baking-school-depth-yeasted-angel-buttermilk-biscuits/