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sweet onion sauce on a table with a whole onion, garlic, and honey
4 from 6 votes

Roasted garlic and sweet onion sauce

An easy sauce recipe that roasts sweet vidalia onions along with garlic. After blending, it becomes a smooth, creamy, sweet sauce. You can thin it down to make a salad dressing too.
Prep Time5 mins
Cook Time45 mins
Total Time50 mins
Servings: 8 servings, 2Tbs per serving
Calories: 85kcal
Author: Ask The Food Geek


  • 1 sweet onion (like vidalia or walla walla)
  • 4 cloves garlic with skin on*
  • ¼ cup olive oil
  • 3 Tbs apple cider vinegar
  • 1 Tbs honey
  • 1 Tbs mustard



  • Heat oven to 425 degrees
  • Cut ends off onions and peel them. Cut in half across the equator. Brush liberally with olive oil and place on roasting pan.
  • Separate cloves of garlic and brush with oil. Leave the skin on (or they will burn). If you don't have the skin on, brush with oil then wrap in foil. Place on roasting pan.
  • Roast until the edges char - if some are done early, take those ones out and return the rest. It should take about 45 minutes, but check after 25 minutes to be safe.


  • Remove the garlic from the skins. Roughly chop the onion or pull it apart. Put the roasted onions, 1 garlic clove, and the remaining ingredients (including olive oil) in a blender. Process into a smooth sauce.
  • Taste, add more garlic if you want, and season with salt and pepper.


  • Add a tablespoon of olive oil and/or vinegar to the blender to thin the dressing down (if you want it to be thinner). I use the 'sauce' recipe on salads without thinning it at all, but it is up to you.


Serving: 2Tbs | Calories: 85kcal | Carbohydrates: 5g | Fat: 6g | Sodium: 25mg | Potassium: 55mg | Sugar: 4g | Vitamin C: 2.5mg | Calcium: 11mg | Iron: 0.2mg