Preheat the oven to 350 degrees F (175 degrees C).

Butter a 7 x 11-inch baking pan. Separate dough into 8 pieces; flatten each into a circle. Wrap one biscuit around each apple half; place in the pan, seam-side down.

Combine sugar, water, butter, and vanilla extract in a small bowl. Pour mixture over dumplings; sprinkle with cinnamon. Bake until golden, 35 to 40 minutes. Serve hot.