Authentic Beef and Onion Fajitas Recipe from Mexico

Ingredients

• 1 cup coarsely chopped white onion
• 10 medium garlic cloves
• 5 serrano peppers
• 0.5 cup fresh lime juice
• 2 tbsp worcestershire sauce
• 2 tbsp brown sugar
• 4 tsp chili powder
• 1.75 lb (794 g) top sirloin steak
• 2 tbsp butter
• 2 tbsp olive oil
• 3 medium onions cut into narrow wedges
• 3 bell peppers cut into narrow strips
• 12 flour tortillas steamed
• 2 limes wedged
• 1 lb (454 g) pepper jack cheese grated
• 1 cup cheddar cheese
• 1 cup sour cream
• 1 cup salsa