Spray a baking dish with non-stick spray. Heat oven to 350 degrees.
Wash and dry apples. Peel them if you would like, or leave them unpeeled.
Evenly cut apples into bite-sized pieces. Carefully unroll the crescent roll dough and separate into triangles. Place a small handful of apple pieces (about 2 tablespoons per triangle) in the center of each crescent.
Roll the dough up and place the apple filled dough (seal side down) into the bottom of the baking dish.
In a small bowl, combine melted butter, cinnamon, vanilla and both sugars. Spoon the sugar mixture over the top of the dumplings evenly.
Pour the Mountain Dew around the edges of the pan and in between each dumpling.
Bake uncovered for 40 minutes until the top of the dumplings are golden brown.