fajitas - grilling directions?

From forum member Fidel this has worked for me...very, very good...

For the Marinade :
5-6 cloves Garlic, minced
1/2 cup chopped fresh Cilantro
1 Jalapeno, seeded and diced
3 juiced Limes
1/2 cup Canola or Vegetable Oil
1 Tbls. Onion Powder
1 Tbls. crushed Red Pepper
1 Tbls. ground Cumin
1 Tbls. Black Pepper
1 Tbls. Ancho Chili Powder
1 Tbls. Salt
1 tsp. Kitchen Bouquet (optional)

Combine all ingredients to make the marinade.

Additional Ingredients :
1.25 to 1.5 pound Flat Iron Steak
One large Yellow sweet Onion
One Bell Pepper
2 Tbls. Butter
1 Tbls. Canola or Vegetable Oil
Kosher Salt
Cumin
Ancho Chili Powder to taste

Clean the steak of any external fat and silver skin. Soak in the marinade overnight.
Get the egg to searing temps for the steak. Sear for 90 seconds per side and
remove, wrap tightly in foil to rest.
Heat a cast iron skillet direct over the lump for at least 10-15 minutes. As it preheats
cut the bell pepper and onion into 1/4” thick slices.

Add the butter and oil to the skillet. Once the butter melts and begins to smoke add
the sliced onions and peppers. Season to taste with cumin, ancho chili powder, and
kosher salt. Stir occasionally, allowing the vegetable to slightly char on the edges if
desired. As the vegetables cook to near completion, slice the flat iron steak into 1/4”
- 1/2” thick slices on a diagonal, trying to cut against the grain as much as
possible. Add the slices of steak and all the rendered juices to the vegetables. The
meat will go from very rare to medium rare in just a minute or two. Keep the skillet
uncovered at all times to allow the juices and liquids from the vegetables to reduce
as everything cooks.
Once the steak is cooked to your liking remove from the heat, squeeze 1/2 of a
fresh lime over the fajitas, and allow to rest and cool for a few minutes.

Serve with warmed flour tortillas and pico de gallo.

I'm unfamiliar with what beef sirloin "flap" is . . . however, if it's red meat we have one question: "Low and slow, or hot and fast?" And I'd venture that with beef, unless you're doing a stew or a fatty roast cut, you're definitely going to go with hot and fast. You don't need a digital damper system to do this. Crank the egg up to a good 600 and then sear your beef MR, remove and rest for 10 minutes, then slice thinly AGAINST or CROSS the grain for fajita meat. Dredge the meat (and I'm assuming grilled peppers and onions) in any leftover marinade--fresh marinade that wasn't used to marinate previous to cooking.