Tennessee Onions

From: delish.com Prep Time: 20 minutes
Serves:6-8 Cook Time: 130 minutes
Directions
Ingredients
- Arrange a rack in center of oven; preheat to 350°. Lightly grease a 13” x 9” baking dish with cooking spray.
- Arrange an onion on its side on a cutting board. Using vertical slices, cut onion into 1/4"-thick rounds. Separate rounds into individual rings. Restack rings, starting from the largest piece to the smallest (mimicking the original shape of the rounds) in prepared dish. Repeat with remaining onions.
- In a small bowl, mix parsley, mustard, garlic powder, seasoned salt, oregano, kosher salt, cayenne, and black pepper. In a medium bowl, toss mozzarella, cheddar, and Parmesan.
- Sprinkle onions with seasonings and gently toss to coat. Dot onions with butter. Add 1/2 c. water to bottom of pan and tightly cover with foil.
- Bake onions until tender, 75 to 90 minutes (the centers should be easily pierced with a fork or a metal cake tester). Remove from oven and sprinkle with cheese mixture.
- Continue to bake until cheese is melted and bubbling around the edges, 5 to 7 minutes. Turn on broiler. Broil, watching closely, until cheese is browned in a few spots, 1 to 2 minutes more. Top with parsley.
- 2 1/2 lb. sweet Vidalia onions (3 large or 4 medium), peeled
- 1 tsp. dried parsley
- 1 tsp. dry mustard
- 1 tsp. garlic powder
- 3/4 tsp. seasoned salt
- 1/2 tsp. dried oregano
- 1/2 tsp. kosher salt
- 1/4 tsp. cayenne pepper
- 1/4 tsp. freshly ground black pepper
- 1 cup shredded mozzarella
- 1 cup shredded sharp cheddar
- 1/2 cup finely grated Parmesan
- 4 Tbsp. unsalted butter, cut into cubes
- Chopped fresh parsley, for serving
Notes:
Make sure to separate the rings from one another when placing them in the baking dish. It's the best way for the seasonings and cheeses to penetrate the onions as they bake.