Preheat oven to 450°F (230°C). Pour melted butter into a 9×9-inch baking dish, making sure it evenly coats the bottom.
In a large bowl, whisk together flour, baking powder, sugar, and salt.
Add buttermilk and shredded cheddar cheese to the dry ingredients. Stir until just combined; do not overmix.
Pour the biscuit batter over the melted butter in the dish. Use a spatula to spread evenly.
Cut the unbaked dough into 9 squares (3x3 grid) to help with portioning after baking.
Bake for 25-28 minutes, or until golden brown on top and set in the center.
Let cool for a few minutes before serving. Enjoy warm for the best flavor!