• Flaky sea salt, optional
• Fresh flat-leaf parsley leaves, for garnish
To make tomato relish: Preheat oven to 425 degrees. Toss tomatoes with 1 tablespoon olive oil and spread them in single layer in a baking dish. Season with salt and black pepper to taste, and roast until tomatoes are crinkled and browned and any liquid in the pan is reduced, 18 to 20 minutes. Let cool.
In wide nonreactive saucepan, heat remaining 1 tablespoon oil over medium-high heat. Add mustard seeds and cook until they pop, about 30 seconds. Add onion, garlic, red pepper flakes, ginger and a pinch of salt. Cook, stirring frequently, until onion has softened, about 3 minutes. Add roasted tomatoes and stir to combine, but take care to keep tomatoes intact. Add orange juice and Worcestershire sauce. Cook, stirring gently, until juices have thickened to a jammy consistency, about 5 minutes. Taste and season with salt and black pepper. Store in an airtight container in the refrigerator for up to a week.
To prepare steak: Season hanger steak with fine sea salt and pepper. Let sit at room temperature for at least 20 minutes before cooking.