Preheat the oven to 400 degrees F.
Combine the flour, sugar, baking powder, garlic powder, Old Bay, and salt using a whisk. Once combined, set it aside.
In another bowl, mix the melted butter, oat milk, egg, and vinegar. Mix to combine.
Pour the wet ingredients into the dry, mixing with a spatula until the flour is just moistened. Lightly fold in the shredded cheddar. Do not overmix.
Using an ice cream scoop, scoop equal-sized drop biscuits onto a greased baking sheet about 2 inches apart from one another.
Bake in a preheated oven for 14-15 minutes or until the bottoms are lightly browned.
Meanwhile, melt the 4 tablespoons of butter. Stir in the garlic powder and parsley. Using a pastry brush, liberally coat each biscuit in herb butter.
Place into a bread bowl and serve warm.