In a large bowl, add the baking mix, sugar, garlic powder, and butter, and cut butter into the dry ingredients (just like you would for pie crust) until it forms pea size particles.
In another bowl, add the half-and-half, cheddar cheese, chives, and eggs, and mix well until the eggs are light and fluffy and well mixed in.
Add the wet ingredients to the dry ingredients, and mix well until dough forms a ball. Line a cookie sheet with parchment paper, and drop the biscuits (about a tablespoon amount) onto the parchment paper. Bake at 425 for 8 to 10 minutes, or until biscuits are golden brown.
While biscuits are baking, melt the 1/2 cup of butter with the coarse ground garlic salt, and stir well, and set aside.
When biscuits are done baking, remove from oven and brush garlic butter on tops of biscuits. Garnish tops with additional shredded cheese and chopped chives.