Preheat the oven to 350º F. Unroll the crescent roll dough and place one slice of apple at the thickest part and roll-up.
Place the rolled dumplings in a greased baking dish.
Add the butter, vanilla, cinnamon, and brown sugar to a small saucepan over medium heat and melt the butter and stir everything together.
Pour the melted butter mixture over the dumplings.
Pour the can of 7-UP around the dumplings (not on top) and bake in the oven for 35 minutes.
Serve immediately.