Ingredients

• 3 tablespoons vegetable oil, divided
• 1 medium onion, chopped
• 4 garlic cloves, chopped
• 1 Fresno chile or red jalapeño, seeded, chopped
• Kosher salt, freshly ground pepper
• 1 freshly ground pepper
• 1 tablespoon tomato paste
• 1/2 cup Worcestershire sauce
• 1/2 cup red wine vinegar
• 1/4 cup (packed) dark brown sugar
• 2 tablespoons whole grain mustard
• Few dashes of hot sauce
• 1 1/2 pounds hanger steak, center membrane removed, cut into 4 pieces

Instructions

1. Heat 2 tablespoons oil in a small saucepan over medium-high heat. Add onion, garlic, and chile; season with salt and pepper. Cook, stirring often, until soft, about 5 minutes.
2. Add tomato paste to saucepan and cook, stirring, until beginning to darken, about 1 minute. Stir in Worcestershire sauce, vinegar, brown sugar, mustard, and hot sauce; simmer until slightly thickened, about 5 minutes. Transfer to a blender and purée with 1/2 cup water until smooth. Strain through a fine-mesh sieve into a small bowl, if desired. Set sauce aside.
3. Heat remaining 1 tablespoon oil in a large skillet over medium-high heat. Season steak with salt and pepper and cook, turning occasionally, until deeply browned and an instant-read thermometer registers 130°F for medium-rare, 8–10 minutes.
4. Transfer meat to a cutting board; let rest 5 minutes before slicing. Serve with sauce.
5. DO AHEAD: Steak sauce can be made 1 week ahead. Cover and chill.