Preheat the oven to 475°F. Line a large rimmed baking sheet with parchment paper. Set aside.
In a medium bowl, with a pour spout, combine ½ cup of the melted butter with the cold buttermilk. Stir to incorporate fully.
In a large mixing bowl, combine the self-rising flour, granulated sugar, baking powder, garlic salt, and 2 tablespoons of fresh chopped parsley. Once all those ingredients are combined, add the shredded cheddar cheese and toss the cheese in the flour mixture so that all the cheese is coated.
Add the buttermilk and melted butter mixture to the flour mixture and gently combine with a wooden spoon until all the liquid is incorporated into the flour. Do not overmix the batter.
Using a 2-inch cookie scoop, scoop out the biscuits onto the prepared baking sheet 2 inches apart.
Bake for 12 to 14 minutes or until lightly golden on the edges.
In a small dish, melt the remaining ¼ cup unsalted butter and add the remaining 1 tablespoon chopped fresh parsley. Stir to combine.
When the biscuits come out of the oven, using a pastry brush, brush them with the additional parsley-infused melted butter.
Allow the biscuits to cool for 5 minutes on the baking sheet before removing them to serve.