For the noodles
01 -
12 oz (340 g) wide egg noodles
02 -
1 tablespoon unsalted butter
03 -
Salt for the pasta water
For the beef and sauce
04 -
1 1/2 lb (680 g) sirloin steak, sliced thinly across the grain
05 -
1 teaspoon kosher salt, divided
06 -
1/2 teaspoon black pepper
07 -
2 tablespoons olive oil, divided
08 -
3 tablespoons unsalted butter, divided
09 -
12 oz (340 g) cremini mushrooms, sliced
10 -
1 medium yellow onion, thinly sliced
11 -
3 cloves garlic, minced
12 -
2 tablespoons all-purpose flour
13 -
2 cups (480 ml) low-sodium beef broth
14 -
1 tablespoon Dijon mustard
15 -
1 tablespoon Worcestershire sauce
16 -
3/4 cup (180 g) full-fat sour cream
17 -
2 tablespoons chopped fresh parsley