Prepare the seasonings in a bowl with the juice and rub all over the steak. Allow to sit, covered in the fridge for 24 hours or you can even freeze it like that.
Skirt or Flank Steak, 1 Tablespoon Kosher Salt, 1 Tablespoon Chili Powder, 2 teaspoons Smoked Paprika, 1 ½ teaspoons Cumin, 1 Tablespoon Garlic Powder, 1 Tablespoon Onion Powder, 1/4 teaspoon Cayenne, 1/4 Cup Grapefruit Juice
For the Marinade
Using a garlic press, press the garlic and ginger through so that they are very fine. This opens the two up giving you far more flavor than slicing or mincing.
4 Cloves Garlic, 2 Tablespoons Ginger
Combine all of the ingredients in a ziploc bag and squish together thoroughly. Set aside.
1/4 Cup Rice Vinegar , 1/2 Cup Pineapple Juice , 1 Cup Soy Sauce, 2 Tablespoons Light Brown Sugar , 1 Pinch Crushed Red Chili Flakes , 3 Scallions
Add marinade to meat and marinate in the fridge for 1-4 hours. You can push to 24 hours if necessary but the acid is starting to break down the meat so I prefer 1-3 hours and then to make a sauce for more flavor using the reserved marinade.
When you’re ready to cook, let the meat rest on the counter for 15-20 minutes, then pat dry with a paper towel. Remove the marinade to a sauce pan to save the remaining marinade to make a sauce.
Heat a grill to high heat and rub the grates with an oil soaked paper towel. Place the meat on the grill to sear it for about 3-4 minutes, flip to sear the other side for another 2-5 minutes and then remove to a cutting board to rest for 5 minutes before slicing.
For the Sauce
Add remaining marinade to a sauce pan and bring to a boil for 3 minutes or until you have reduced to a thick sauce, stirring often so it doesn’t burn.
Remove from heat. Immediately, add 2 tablespoons of butter and swirl the sauce until butter is melted and combined into the sauce. Serve over steak with additional scallions.