Steak Sandwich With Caramelized Onions And Horseradish Mayo

• 3 Cup very thinly sliced sweet onion (about 1 large)
• 3 Tablespoon olive oil, plus more for oiling grill
• 2 Teaspoon thyme leaves
• 1 Tablespoon balsamic vinegar
• 2 Teaspoon brown sugar
• salt and pepper
• 1/3 Cup mayonnaise
• 1 Tablespoon prepared horseradish
• 1 Teaspoon lemon juice
• 2 (8 oz) beef strip loin steaks
• 4 Slice sourdough bread (8 if making closed sandwiches)
• 1/4 Cup roasted red pepper, thinly sliced
• 1/2 Cup arugula or watercress, for garnish, if desired

1. Preparation
2. 1.Preheat a grill or grill pan to medium-high.
3. 2.In a large non-stick skillet set over medium-low heat, add onions, oil and thyme and cook covered, stirring occasionally until soft and translucent, about 10 minutes. Add vinegar and sugar and cook until caramelized, about 4 minutes. Season to taste with salt and pepper and set aside.
4. 3.Meanwhile, combine mayonnaise, horseradish and lemon juice in a bowl and stir to blend. Season to taste with salt and pepper and set aside
5. 4.Season steak with salt and pepper and place on an oiled grill. Cook, turning once until desired doneness is reached, about 3 to 4 minutes per side for medium-rare. Let rest, lightly covered with aluminum foil for 5 minutes before slicing.
6. 5.Toast or grill bread and spread one side of each slice with mayonnaise. Layer with red peppers, onions, steak, and arugula.

very, olive oil, thyme, balsamic vinegar, brown sugar, salt, mayonnaise, horseradish, lemon juice, beef strip loin steaks, bread, red pepper, arugula

Taken from www.epicurious.com/recipes/member/views/steak-sandwich-with-caramelized-onions-and-horseradish-mayo-50101830 (may not work)