Peel and core apples. Cut each apple into 4 slices. Unroll crescent rolls and separate each roll into 4 sections, pinching the seams of two rolls together, making a total of 8 rectangles. Roll each apple slice in one rectangle of dough. Place into a 13 x 9 baking dish.
Melt butter, then add sugar and vanilla and barely stir. Pour mixture over apples. Pour Mountain Dew around the edges of the baking dish. Sprinkle with cinnamon.
Bake at 350* for 40 minutes. Serve with ice cream.