Preheat oven to 425 degrees F.
Add the 1 stick of melted butter to the bottom of a 9 x 13 Glass baking pan.
In a large bowl, combine the 4 cups of biscuit mix, sour cream, and 7 UP.
Combine until just mixed, but do not overwork. Dough will be VERY sticky.
Line your work space with parchment paper, and place the 1 cup of extra mix on top.
Flour a biscuit cutter and your hands.
Place dough on the work space, and sprinkle with extra biscuit mix.
Form a 1-inch thick disc. (thumb tip to your first joint is the right thickness) Cut biscuits from this disk.
Place each cut biscuit into the buttered dish. Keep in mind, dough should make the perfect amount of biscuits to line this size pan.
If dough becomes too sticky add more biscuit mix.
Repeat the process until all biscuits have been cut.
Once they are all cut, brush them with the 1 tablespoon of melted butter.
Bake at 425 F. for 20 minutes or until slightly golden brown.
Remove biscuits from oven and allow to cool for about 10 minutes before enjoying.