Slice the beef into strips. Slice the bell peppers and onion as well.

Finely chop the white onion, tomato, and serrano pepper. Cut open the avocado, remove the pit, and scoop the flesh into a deep plate or bowl. Mash the avocado and mix in the finely chopped vegetables. Sprinkle with salt and squeeze in lime juice.

Once the beef, bell peppers, and onion are sliced, add them to a skillet, griddle, or comal. Cook and season with salt and pepper. Once cooked, add the sauces to keep everything juicy.

When the fajitas are ready, serve them with guacamole, panela cheese, and cucumber cut into half-moons on a large plate. Serve the cooked beans in a bowl.

Serve with flour and corn tortillas.