2
4 onion or kaiser buns, halved
2 tsp olive oil
1 large onion, finely chopped
1/4 tsp granulated sugar
1/4 tsp salt
1/4 tsp ground black pepper
1 to 2 tbsp white vinegar
2 tsp dried tarragon leaves
1/3 cup mayonnaise, preferably light
2 tbsp pitted and finely chopped black olives, optional
2 oil-packed sun-dried tomatoes, halved, and finely chopped
170-g can chunk light tuna
2 cups chopped spinach, or arugula
Heat oil in a medium-size frying pan. Add onion. Sprinkle with sugar, salt and pepper. Stir often over medium heat until onion turns golden, 5 min. Add 1 tbsp (15 mL) vinegar and tarragon. Stir constantly until liquid has evaporated, 1 min. Taste, then add more vinegar, if needed. Remove from heat. In a large bowl, stir mayonnaise with olives and tomatoes. Stir in onion mixture. Crumble in tuna. Stir in spinach. (If making ahead, cover and refrigerate tuna mixture up to 2 days.) Spoon over base of each bun. Top with bun lids. Serve or wrap and refrigerate. Sandwiches keep well, wrapped and refrigerated, up to 1 day.
Calories 327, Protein 15.9g, Carbohydrates 39.4g, Fat 11.6g, Fibre 2.4g, Sodium 752mg.