Preheat the oven to 425°F / 220°C.
Place the salted butter in a 9x13-inch baking dish.
Transfer the baking dish to the oven and heat until the butter is fully melted.
Carefully remove the baking dish from the oven and set it aside.
In a large mixing bowl, combine the Bisquick, 7-Up, and full-fat sour cream.
Stir until the ingredients are evenly combined. The dough will be sticky.
Lightly dust a clean work surface with additional Bisquick or flour.
Transfer the dough onto the prepared work surface.
If the dough is too sticky to handle, sprinkle a small amount of additional Bisquick over the dough and gently work it in only until manageable.
Pat or roll the dough into a circle approximately 1 inch thick.
Cut the dough into rounds using a biscuit cutter, round glass, or another round cutter.
Place the biscuit rounds directly into the baking dish with the melted butter.
Arrange the biscuits evenly in the dish.
Bake for 10 to 12 minutes, or until the biscuits are golden brown on top and baked through.
Remove the baking dish from the oven.
Allow the biscuits to rest in the pan for several minutes so they can absorb the melted butter.
Serve warm.