Ingredients
- 2 Tbs. ketchup
- 1 Tbs. Dijon mustard
- 1 jarred hot cherry pepper, stemmed, seeded, and chopped
- 1 tsp. red wine vinegar
- 1 lb. beef sirloin tips (flap meat), cut into 1-inch pieces
- Kosher salt and freshly ground black pepper
- 3 Tbs. olive oil
- 1 small yellow onion, halved and thinly sliced
- 6 oz. sliced white mushrooms (2 cups)
- 1-1/2 cups shredded sharp Cheddar
- 4 long rolls, split and lightly toasted
- 1-1/2 oz. baby arugula
- Mix the ketchup, mustard, cherry pepper, and vinegar in a small bowl and set aside.
Preparation
Step 1
In a food processor, pulse half of the beef until just coarsely chopped. Transfer to a bowl. Repeat with the remaining beef. Toss the beef with 1/2 tsp. salt and 1/2 tsp. pepper.
Heat 1-1/2 Tbs. of the oil in a heavy 12-inch skillet over medium-high heat until shimmering hot. Add the beef and cook, stirring occasionally, until it loses most of its raw color, about 3 minutes. Transfer to a plate. Heat the remaining 1-1/2 Tbs. oil in the pan. Add the onion and 1/4 tsp. salt; cook, stirring often, until beginning to soften and brown, about 4 minutes. Add the mushrooms and 1/4 tsp. salt; cook, stirring often, until they soften and begin to release their juice, about 2 minutes. Add the ketchup mixture and beef and any accumulated juices. Cook, stirring often, until heated through, about 2 minutes. Stir in the cheese until melted, about 1 minute more.
Split the rolls almost through lengthwise and pile on the steak and arugula. Cut the sandwiches in half, and serve.