Preheat the oven to 350°F (175°C).

In a large skillet over medium-high heat, cook the chopped roast beef for a couple of minutes, stirring occasionally. Tip: Make sure not to overcrowd the skillet to ensure even cooking.

Add the diced onions and bell peppers to the skillet, cooking until softened, about 3-5 minutes.

Stir in the chopped garlic and steak spice, cooking for an additional 3 minutes to enhance the flavors.

Reduce the heat to low and add the cheddar soup and milk to the skillet. Stir well to combine.

Mix in the shredded cheddar cheese until melted and remove the skillet from heat.

Grease a 9 x 13 inch baking dish with cooking spray for easy removal after baking.

Spread the roast beef mixture evenly in the baking dish. Tip: Ensure the mixture is evenly distributed for consistent cooking.

In a mixing bowl, combine the biscuit mix (set aside the seasoning packet), shredded cheddar cheese, and milk. Stir until smooth.

Pour the batter over the roast beef mixture in the baking dish, spreading it gently to cover the filling.

Bake in the oven for 50-55 minutes, or until the biscuit topping is golden brown. Tip: Check for doneness by inserting a toothpick into the biscuit topping; it should come out clean.

Remove from the oven and mix the melted butter with the seasoning packet in a small bowl. Brush this mixture over the biscuit topping for extra flavor.

Let the cobbler rest for about 5 minutes to allow the biscuit to absorb the butter.

Serve and enjoy your delicious Cheddar Bay Philly Cheese Steak Cobbler!