Cabernet-Balsamic Burgers with Sautéed Mushrooms & Onions

Ingredients

• 1.5 cups baby arugula 
• 2 tablespoons balsamic vinegar 
• 0.3 cup cheese blue crumbled
• 0.5 cup wine dry red
• 1.5 teaspoons thyme leaves fresh chopped
• 1  garlic clove minced
• 1.5 pounds ground sirloin 
• 9 ounce hamburger buns whole-wheat
• 0.3 cup mayonnaise light
• 8 ounce mushrooms sliced
• 5 teaspoons olive oil divided
• 4 cups onion red thinly sliced
• 0.8 teaspoon salt divided

Equipment

• bowl
• frying pan
• paper towels
• grill

Directions

1. Heat a large nonstick skillet over medium-low heat.
2. Add 2 teaspoons olive oil to pan; swirl to coat.
3. Add onion and thyme; cook 17 minutes or until golden and very tender, stirring occasionally. Increase the heat to medium-high; add wine, vinegar, and 1/4 teaspoon salt. Cook for 6 minutes or until the liquid almost evaporates, stirring occasionally.
4. Remove onion mixture from pan.
5. Wipe pan clean with paper towels.
6. Heat pan over medium-high heat.
7. Add the remaining 3 teaspoons oil to pan; swirl to coat.
8. Add mushrooms and 1/4 teaspoon salt; saut for 8 minutes or until mushrooms brown and liquid mostly evaporates.
9. Preheat grill to medium-high heat.
10. Coarsely chop 1 cup onion mixture, and stir chopped onion mixture into beef. Divide the beef mixture into 6 equal portions, gently shaping each into a 1-inch-thick patty. Press a nickel-sized indentation in center of each patty.
11. Sprinkle the patties with remaining 1/4 teaspoon salt.
12. Place patties on a grill rack coated with cooking spray, and grill for 4 minutes on each side or until done.
13. Combine mayonnaise, blue cheese, and garlic in a bowl, and mash well with a fork.
14. Spread the top halves of buns evenly with mayonnaise mixture. Arrange 1/4 cup arugula on bottom half of each bun; top each bottom half of bun with 1 patty, about 2 tablespoons remaining onion mixture, about 1/4 cup mushrooms, and top half of bun.