Preheat the oven to 450°F and coat a 9×9-inch glass or ceramic baking dish with nonstick cooking spray. In a medium bowl combine the flour, sugar, baking powder, salt and garlic powder, whisking briefly to distribute the leavening and spices evenly.

Pour in 1¾ cups of buttermilk and stir gently until a thick, sticky batter forms, adding a little more buttermilk if the mixture seems too dry. Fold in the shredded cheddar and chopped chives until they are evenly dispersed throughout the dough.

Melt the stick of butter in a microwave-safe bowl or directly in the baking dish if preferred. Pour the melted butter into the prepared dish, swirling to coat the bottom. Transfer the biscuit dough on top of the butter and use lightly oiled or sprayed hands to spread it into an even layer.

Use a sharp knife to mark the dough into nine equal squares, cutting just through the top layer. This will make serving and pulling apart the biscuits easier once baked. Place the pan on the middle rack of the oven and bake for twenty-five to thirty minutes, rotating the dish halfway through, until the tops are golden brown and a toothpick inserted in the center comes out clean.

Allow the biscuits to rest in the pan for five minutes before serving so the butter can settle and the centers finish cooking through.