Caramelized Onion and Mushroom Turkey Burger – The New Perfect

Ingredients

• 4 small yellow onions ( peeled and sliced into half-moons)
• 2-3 tbsp olive oil
• 1 tbsp balsamic vinegar
• 1 lb cremini (baby bella) mushrooms ( cleaned and quartered)
• 2 tsp minced garlic
• 1 lb ground turkey
• 1 tsp Dijon mustard
• 1/2 tsp dried thyme
• 1/2 tsp dried sage
• 1/2 cup crumbled feta or blue cheese
• Iceberg lettuce (for “lettuce bun”)