• Heat the oven to 350°F (175°C).

Prepare the filling:

• Place a large non-stick skillet over medium-high heat. Add the ground beef, breaking it up as it cooks, then add the diced onion and garlic and continue cooking until the meat is browned and the onion is softened.
• If there is excess fat, drain it from the skillet. Stir in the condensed cheddar soup, condensed cream of mushroom soup, 1/2 cup milk, salt, and pepper until the mixture is smooth and heated through.
• Fold 1 cup of shredded cheddar into the beef mixture, mixing until incorporated, then remove the skillet from the heat.

Assemble and bake:

• Spray a 9 x 13-inch baking dish with cooking spray to prepare it for the casserole.
• Transfer the beef mixture into the prepared baking dish and spread it into an even layer.
• Evenly sprinkle 1 cup of shredded cheddar over the beef layer.
• In a large bowl, combine the Cheddar Bay biscuit mix (set the seasoning packet aside). Add 2 cups milk and 1 cup shredded cheddar to the mix and stir until the batter is smooth without large lumps.
• Spoon or pour the biscuit batter over the cheese-topped beef, spreading gently to cover the surface as evenly as possible.
• Bake in the preheated oven until the biscuit topping is golden brown across the top and set, about 50 to 55 minutes.

Finish and serve:

• While the cobbler is hot from the oven, combine the melted butter with the seasoning packet reserved from the biscuit mix and brush this mixture over the top to add flavor and shine.
• Allow the casserole to rest for about 5 minutes so the filling can thicken and the topping sets slightly.
• Sprinkle chopped fresh parsley over the top if desired, slice into portions, and serve warm.