Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.

In a large bowl, whisk together the flour, baking powder, salt, and garlic powder (if using).

Add the cold, cubed butter to the flour mixture. Use a pastry cutter, fork, or your fingertips to work the butter into the flour until the mixture resembles coarse crumbs with some pea-sized butter pieces remaining.

Stir in the shredded cheddar cheese and chopped chives until evenly distributed.

Make a well in the center of the dry ingredients. Add the Greek yogurt and lightly beaten egg. Gently stir with a fork until a shaggy dough forms. Do not overmix.

Turn the dough out onto a lightly floured surface. Gently knead 3-4 times just to bring it together. Pat the dough into a 1-inch thick circle. Use a 2.5-inch round biscuit cutter or glass to cut out biscuits. Re-roll scraps once to cut more.

Place the biscuits on the prepared baking sheet, about 1 inch apart. Brush the tops with melted butter. Bake for 12-15 minutes, or until puffed and golden brown.

Let the biscuits cool on the baking sheet for 5 minutes before serving warm.