Preheat oven to 375°F. Grease a 9x13-inch baking dish.
In a large bowl, mix cooked protein, soup, milk, frozen vegetables, cheese, and garlic powder. Add salt and pepper to taste.
Pour the filling mixture into the baking dish and spread evenly.
Prepare biscuit topping per package instructions. Drop spoonfuls of dough over the filling.
Bake uncovered for 25–30 minutes, until biscuits are golden and filling is bubbly.
Mix melted butter, garlic powder, and parsley. Brush over biscuits as soon as it comes out of the oven.
Let rest 5–10 minutes before serving.