Preheat oven to 450°F (230°C). Place a 6-cup popover pan in oven to preheat.

For popovers: In a large bowl, whisk together milk, melted butter, eggs, and vanilla until frothy, about 1 minute. Whisk in flour, sugar, and salt until batter is slightly lumpy, about 30 seconds.

Carefully remove hot pan from oven, and spray with cooking spray. Divide batter among prepared cups.

Bake for 12 minutes. Rotate pan, and reduce oven temperature to 350°F (180°C). Bake until tall, golden brown, and crisp, 15 to 20 minutes more, covering with foil to prevent excess browning, if necessary.

Meanwhile, for topping: In a small bowl, whisk together sugar and cinnamon.

Carefully remove hot popovers from pan. Brush melted butter onto popovers, and generously sprinkle with cinnamon sugar to coat. Serve immediately with Peach Compote.