1 cup red wine vinegar ((or white or apple cider vinegars))
2 tbsp brown sugar
2 tsp fresh rosemary (chopped)
1/2 tsp kosher salt
1/4 tsp black pepper
1 pinch red pepper flakes (optional)
4 large onions ((See Note 1))
4 tbsp butter
1 tsp fresh rosemary (chopped)
Categories
side dishes
Cuisine
Melting Pot
Steps
Blend marinade ingredients in small bowl and pour into a baking dish that will hold all 8 onion halves. I use 8x8" baking pan or round 12" baking stone (pictured) depending on size of onion.
Trim the end of onions and cut horizontal (leaving skin on) and place cut side down in marinade. Marinate overnight covered in refrigerator.
Preheat oven to 400°F. Flip the onions over in the marinade, and lay on the flat bottom of each side. Top each onion with 1/2 tablespoon of butter and remaining teaspoon of rosemary.
Roast uncovered in oven for 1 hour or until golden brown and tender, basting once or twice during roasting. Remove from heat, spoon reduced sauce over and sprinkle with parsley or more fresh chopped rosemary. Remove outer skins before eating and serve.
Nutitrion
Serving Size: 1 oz
Calories: 90 kcal
Carbohydrates: 8 g
Protein: 1 g
Fat: 6 g
Saturated Fat: 4 g
Cholesterol: 15 mg
Sodium: 203 mg
Sugar: 5 g
Reviews
Cindy on 2026-01-30 (5 stars): The photos show thick slices of onion but the recipe refers to halved onions. Could you please clarify?
J Fischer on 2026-01-10 (5 stars): I made these for my mom. As she is getting older and not able to cook as much, I am doing more of the cooking. She’s a tough judge in the kitchen. She loves onions and loves vinegar. She gobbled them up!
Nancy Rose on 2025-10-19 (5 stars): I’m roasting these onions now….. the smell is amazing!! They look so delicious.
Tiny on 2024-11-28 (4 stars): 4 stars as is, but 5 stars if you make the following modifications:
Marinate for 2 days if you can (to help break down onion fibers and infuse flavors).
Use 1.5 cups chicken broth (instead of water), and 0.5 cups red wine vinegar (reduced from 1 cup).
Mine needed to be cooked for at least 1.5 hours, basting every 10-15 minutes until golden brown.
Add salt and pepper to taste before eating (needed salt).
Enjoy!
Ruby on 2024-04-08 (2 stars): I liked the concept of this recipe but I think a whole cup of red wine vinegar is way too much. I would use a half cup at the most. The vinegar taste was so strong, I even cooked it for longer hoping it would cook down a bit more but it doesn't cook off. I think Id like to see this recipe with less vinegar and a bit more brown sugar, next time I make this I will try halfing the liquid content.
Mary on 2023-12-23 (5 stars): Can you make this ahead of time and reheat? What would be the best way to reheat?
