I found the following on the internet
Use only the type of pectin called for in your recipe. Powdered pectin and liquid pectin are not interchangeable in recipes. The preserving books seem to confirm that the reason liquid and powdered pectin may not be interchangeable is that the liquid version is always added after boiling but most types of powdered are added to the raw fruit or juice.
Source
The best way, imho, is to use your basic broiling pan...Put a little water in the bottom before you start, or the pan may warp. Put the rack in your oven as high as it will go (while still allowing the broiling pan with steak to fit), then turn the oven on "Broil".
Leave the oven door cracked (you don't want it to pre-heat, and turn the element off), and cook it like you would on the grill, flipping it halfway through. The radiant heat from the element will give you a little char, though no grill lines, obviously.
Anything over medium rare is going to be a bit chewy. Let it rest, then cut it into strips across the grain of the meat. Flank steak responds well to marinades (my favourite: 1 tbps soy sauce, 1 tbsp sherry, 1 tbsp dijon mustard, 1 tbsp lemon juice, 1 tsp ground ginger.)
You could try to cook it on the stovetop, but that much meat will be too much for most pans.
Best Answer
Per Kenji Alt's Food Lab article on fajitas:
According to the Houston Press, outside skirt stake is extremely rare in the US, as much of it gets exported to Japan due to a quick in the tariffs. The outside cut is tougher, but extremely flavorful. Both are used in similar applications, if you can get them.
Given that any skirt you buy is probably inside skirt, the difference is likely to be moot. In making fajitas, Kenji Alt recommends grilling it over extremely high heat, to get browning flavors on the outside, and not overcook the center. He recommends not cooking it over medium rare.
A couple of pictures: