The first thing is to marinate the beef. You need to do this at least 24 hours head, up to three days.

In a large bowl, mix all the ingredients for the marinade with a wire whisk.

Using a sharp knife, cut a cross hatch pattern on both sides of the meat.

Place the beef an a large zip-lock bag and pour the marinade over it.

Close the bag, squeezing out as much air as possible and seal the bag. Gently squeeze and knead the liquids into the beef, then refrigerate, turning occasionally.

To prepare the meat, heat the grill to high. Cook over direct heat for about 3 to 4 minutes on each side, depending on the thickness. When the internal temperature reaches about 130 degrees, remove from the grill and let it rest.

While the beef is grilling, slice the peppers and onions and heat up a griddle. Drizzle with olive oil and Squeeze the lime juice over the vegetables.

Add some oil to the griddle and let it heat up. Lay the vegetables on the griddle and cook on medium heat, turning occasionally. You want it to be soft and just starting to brown. Add salt and pepper to taste.

After the beef has rested about 15 minutes, slice it thin against the grain.

Wrap the tortillas in a damp towel and microwave for about 3 to 4 minutes - just enough to warm them

Make the guacamole by simply mixing all the ingredients together in a bowl, gently smashing as you stir. Done!

Heat a fajita skillet (or any heavy skillet) and add some oil. When it's searing hot, add the beef and give it a quick sear.

Remove from heat, add some vegetables to the skillet and serve. Be sure to include warm flour tortillas and any other toppings you like, but serve the skillet sizzling!!