2 tablespoons mayonnaise
2 teaspoons ketchup
1 teaspoon chopped pickle or relish
3 teaspoons extra-virgin olive oil, divided Preparation time:5 minutes
1 small red onion, thinly sliced Cooking time:10 minutes
1 cup sliced mushrooms Yields:2 slices
5 cups baby spinach
Freshly ground pepper to taste
4 slices bread
1/2 cup shredded Cheese
1/2 cup sauerkraut
1.For the dressing:Whisk mayonnaise and ketchup in a small bowl until smooth. Stir in the pickle (or relish).
2.To prepare sandwiches: Heat 2 teaspoons oil in a large nonstick pan over medium-high heat. Add onion and cook till golden brown and then add mushrooms,which takes about 4 minutes.
3. Add spinach and cook, until it has wilted, 1 to 2 minutes. Transfer the mixture to a plate.
4.Coat the pan with the remaining 1 teaspoon oil and toast the bread; divide cheese,sauerkraut,spinach mixture and the dressing between the 2 slices; cook until the cheese has melted and the bread is golden brown, 4 to 6 minutes.
5.Transfer sandwich halves to a cutting board. Cut sandwiches in half and serve.