(I halved this and it was the perfect amount for Brian and I)
8 oz mushrooms, thinly sliced
2 stalks celery, thinly sliced on a diagonal
1 lemon, very thinly sliced
1 small red onion, thinly sliced
2 Tbsp olive oil
Kosher salt and pepper
1 2-lb, 2-in.-thick sirloin steak
2 cloves garlic, finely chopped
1 cup ketchup
1⁄4 cup fresh lemon juice
1⁄4 cup Worcestershire sauce
Baked potatoes, for serving
1. Heat oven to 400°F. In a roasting pan, combine the mushrooms, celery, lemon, onion, oil, and 1⁄4 tsp each salt and pepper.
2. Season the steak with 1⁄2 tsp each salt and pepper, rub with the garlic and place on top of the vegetables.
3. In a small bowl, whisk together the ketchup, lemon juice and Worcestershire.
4. Spoon the ketchup mixture over the top of the steak and roast 30 to 35 minutes for medium-rare (when a meat thermometer registers 125°F). Transfer the meat to a cutting board and let rest at least 5 minutes before slicing. Serve the steak with the vegetables and baked potatoes, if desired.