Heat 1 tablespoon butter and Vegetable oil in a large pan over medium-high heat. Season steak with salt and pepper and add to pan. Cook until seared on all sides. (Note: You do not need to cook the meat through. It will cook more in the oven.)
Place sirloin in a large bowl and set aside.
Add remaining butter to pan and cook mushrooms until browned. Add to bowl with sirloin
Add garlic and herbs to pan and cook in whatever juices are left in the pan for 30 seconds.
Add beef consomme, cream of mushroom soup, Worcestershire sauce, and Dijon mustard to pan and bring to a simmer.
Add cream cheese and stir until melted. Pour mixture into bowl with steak and mushrooms.
Add egg noodles, sour cream, and green onions and stir to combine everything.
Season to taste with salt and pepper.
Transfer to a greased casserole dish. Cover with aluminum foil and bake in a 350 degree oven for 25 minutes.
Remove foil, sprinkle mozzarella cheese on top and bake uncovered for 10 to 15 minutes.