Cheesy Beef Stuffed Bell Peppers

Ingredients

• 5 bell peppers (large, halved lengthwise and seeds removed)
• 3 tablespoons olive oil
• 1 1/4 pounds ground beef (lean)
• 1 yellow onion (medium, chopped)
• 2 cloves garlic (minced)
• 1/2 cup diced tomatoes (undrained)
• 1 teaspoon dried oregano
• 1/2 teaspoon ground cumin
• 1 teaspoon salt
• 1/2 teaspoon black pepper (freshly ground)
• 1 cup shredded sharp cheddar cheese (divided)
• 5 ounces mixed greens
• 1 tablespoon white wine vinegar