I love these sweet & sour red onions. They pair nicely with most fish, they add a bit of sparkle to roast chicken, and they’re a delicious topping for pasta dishes that include hard cheeses like parmesan or pecorino.

This recipe was developed by Kate Sherwood, The Healthy Cook. Have a comment, question, or idea? Email Kate at healthycook@cspinet.org.

Time: 30 minutes

Serves: 4

Ingredients

  • 2 red onions, thinly sliced
  • 1 Tbs. + 2 Tbs. extra-virgin olive oil
  • pinch red pepper flakes, more to taste
  • ¼ tsp. + ¼ tsp. kosher salt
  • 2 tsp. brown sugar
  • ¼ cup red wine vinegar
  • 4 6 oz. tilapia or other white fish fillets
  • 2 Tbs. corn starch

Instructions

  1. In a large pan, combine ¼ cup water with the onions, 1 Tbs. oil, pepper flakes, and ¼ tsp. salt. Bring to a boil over high heat and cook, stirring often, until the water boils off and the onions start to sizzle, 5-7 minutes.
  2. Sprinkle the sugar over the onions. Stir until the sugar dissolves and the onions start to brown, 2-3 minutes. 
  3. Stir in the vinegar. Cook until mostly evaporated, about 1 minute. Set aside.
  4. In a large, non-stick pan over medium-high heat, heat the remaining 2 Tbs. oil until shimmering.
  5. Blot the fillets dry with a paper towel (see Tip, below). Season with the remaining ¼ tsp. salt and dust lightly with the corn starch. 
  6. Sauté the fillets until lightly browned, 2-3 minutes. Turn over and sauté until cooked through, 30-60 seconds.
  7. Remove to a plate or platter and top with the onions.

Tip: Starting with defrosted frozen tilapia? Fish that has been thawed needs a lot of blotting with a paper towel to remove excess moisture. A dry surface helps the fish brown instead of steam.

Nutrition Information

Per serving (1 fillet with topping):

  • Calories: 300
  • Total fat: 13 g 
  • Sat fat: 2.5 g
  • Carbs: 11 g
  • Fiber: 1 g
  • Total sugar: 5 g
  • Added sugar: 2 g
  • Protein: 35 g
  • Sodium: 330 mg