Cheesy Ground Beef Quesadillas Recipe

Ingredients

• 1 pound ground beef
• 1 tablespoon vegetable or olive oil
• 1 cup chopped onion
• Kosher salt and freshly ground black pepper ((to taste))
• 3 tablespoons tomato paste
• 1 cup roughly chopped spinach ((or baby kale))
• ½ teaspoon minced garlic
• 1 teaspoon chili powder
• 2 tablespoons minced fresh cilantro ((optional))
• 4 teaspoons unsalted butter ((divided))
• 8 8-inch flour tortillas
• 1 cup shredded sharp cheddar
• 1 cup shredded havarti
• Guacamole, sour cream, salsa, and lime wedges ((to serve))