Ingredients
1 tablespoon canola oil
1 large sweet onion, sliced
1/8 teaspoon salt plus 1/2 teaspoon, divided
2 tablespoons balsamic vinegar
1/2 cup reduced-fat plain Greek yogurt
2 tablespoons low-fat mayonnaise
2 tablespoons white-wine vinegar
4 teaspoons minced shallot
1/4 teaspoon freshly ground pepper
2 hearts of romaine, halved lengthwise and cored
2 4-ounce cans sardines with bones, packed in olive oil, drained
1 cup halved grape or cherry tomatoes
Preparation
1.Place oil, onion and 1/8 teaspoon salt in a small saucepan over medium heat. Cover and cook, stirring occasionally, until the onions are very soft and starting to brown, 12 to 15 minutes. Reduce heat to medium-low if they are browning too much. Stir in balsamic vinegar and simmer, uncovered, until it is reduced to a glaze, 1 to 3 minutes. 2.Whisk yogurt, mayonnaise, white-wine vinegar, shallot, pepper and the remaining 1/2 teaspoon salt in a small bowl. 3.Divide romaine halves among 4 dinner plates or place on a large platter. Spoon the dressing over the salads. Break sardines into two or three pieces each and divide among the romaine halves. Top with the caramelized onions and tomatoes.
