Preheat your oven to broil on high and set your top oven rack on the highest setting in your oven.

Slice your bell peppers and onion into thin wedges. Drizzle your baking sheet with 1 tablespoon of olive oil and evenly mix the peppers and onions in the olive oil. Add 1 teaspoon of flaky sea salt and ¼ teaspoon of black pepper, about 6 pepper grinds.

Pat down your skirt steak with a paper towel to ensure it is dry. On another baking sheet, add 1 tablespoon of olive oil and cover your flank or skirt steak in the oil. Season with 1 ½ teaspoon of flaky sea salt and ¼ teaspoon of black pepper, about 6 pepper grinds.

Place both baking sheets in the oven. The cooking time for the beef flank steak is about 5-6 minutes per side until done to your liking. I like to cook my flank steak in the oven at medium pulling around 140°F as the temperature will rise as the steak rests. Use a meat thermometer or instant-read thermometer to check the internal temperature to your degree of doneness as desired.

The bell pepper and onions should cook in 8-10 minutes, they should be slightly brown on the edges and fork tender.

Rest the steak for 5 minutes before slicing into thin slices against the grain, serve with bell peppers and onions.