In a skillet over medium heat, cook the ground breakfast sausage until fully browned and crumbled. Drain any excess grease and set aside to cool slightly.

Preheat your oven to 400°F (200°C). Pour the 1/2 cup (1 stick) of melted butter into a 9x9 inch baking dish, ensuring the bottom is evenly coated.

In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, granulated sugar, and salt until well combined.

Pour the cold whole milk into the dry ingredients. Add the cooled, cooked sausage crumbles and shredded sharp cheddar cheese.

Using a spatula or wooden spoon, gently mix until just combined. Be careful not to overmix; the dough will be sticky.

Carefully spoon the sticky dough directly into the butter-coated baking dish. Gently spread the dough evenly across the dish, trying not to press down too hard. The butter should begin to "swim" up the sides of the dough.

Using a sharp knife or bench scraper, gently score the top of the dough into 9 squares (3x3 grid). Do not cut all the way through, just score the surface to make it easier to separate after baking.

Bake for 22-28 minutes, or until the biscuits are golden brown on top and cooked through. The internal temperature should be around 200°F (93°C).

Remove from the oven and let cool in the dish for 5-10 minutes before cutting along the scored lines and serving warm.