Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish.
Peel, core, and quarter the apples. In a small bowl, toss the apple quarters with cinnamon and 0.5 cup of the granulated sugar.
Unroll the crescent roll dough and separate into triangles. Place one apple quarter on the wide end of each triangle and roll up, sealing the edges.
Place the rolled apple dumplings into the prepared baking dish.
In a medium saucepan, combine the water, brown sugar, and 0.5 cup of butter for the sauce. Bring to a boil over medium heat, stirring until the sugar and butter are dissolved. Remove from heat and stir in the vanilla extract.
Pour the sauce evenly over the apple dumplings in the baking dish.
Bake for 40-45 minutes, or until the dumplings are golden brown and the sauce is bubbly.
Let cool slightly before serving. Serve warm, drizzled with extra sauce from the pan.
Notes
These apple dumplings are best served warm. You can also add a scoop of vanilla ice cream or a dollop of whipped cream for an extra treat.