Melt butter in saucepan over medium heat on stove top.
Once butter is melted, turn heat on low. Add sugar, vanilla, and Mountain Dew. Stir until dissolved.
Remove from heat and set aside.
Core & cut apple into 8 slices.
Wrap a crescent roll around each slice.
Place wrapped apples in a lightly greased glass square baking dish.
Pour hot butter sauce over the top and the sides of the wrapped apples.
Sprinkle cinnamon on top. Bake for 30 minutes in preheated oven.
Allow rolls to cool for a few minutes before serving. You’ll definitely want to serve these with a scoop or two of vanilla ice cream!