Prepare the guacamole

• Mash the avocado with a fork in a bowl.
• Add the finely chopped tomato, onion and parsley, the lime juice, salt and pepper.
• Mix well and set aside.

Fill and cook the tacos

• Spread the ground beef evenly over each tortilla.
• Place the tortillas meat-side down in a hot pan and cook until browned.
• Flip the tortilla, add the cheddar and mozzarella, fold in half and cook on both sides until golden and crispy and the cheese has melted.

Assemble and serve

• Open the cooked tacos and add the lettuce and guacamole.
• Serve immediately.