Preheat oven to 375 degrees. Thinly slice (1/8-inch thick) potatoes and layer in a 9- by 13-inch pan coated with cooking spray. Top potatoes with onion rings and set aside.
6 medium baking potatoes, 1 large onion, Cooking spray
In a large bowl, whisk together flour and water.
3 tbsp all-purpose flour, 2 1/4 cups cold water
Whisk in barbecue sauce, vinegar, salt, and pepper. Pour over potatoes, cover with foil, and bake for 1 hour; stir every 30 minutes.
3/4 cup barbecue sauce, 1 tbsp white vinegar, 1/2 tsp Salt, 1/8 tsp ground pepper
Remove foil after 1 hour baking time, return potatoes to oven, and continue baking an additional 45 minutes or until potatoes are tender when pierced with a fork.
Notes
Superb side dish for any meal. The barbecue sauce adds a superb kick to the normal roasty.