Preheat oven to 450°F (232°C).
Pour melted butter into a 9x9-inch baking dish.
In a large mixing bowl, combine Bisquick, sour cream, and 7-Up. Stir just until combined (dough will be soft and sticky).
Transfer the dough to the baking dish and gently press it evenly into the pan over the butter.
Using a knife, cut the dough into 9 square pieces (this helps them bake evenly and makes them easy to separate later).
Bake for 12–15 minutes, or until golden brown on top.
Remove from oven and let cool slightly before serving.