In a medium saucepan, combine the broth and dried porcini. Bring to a boil, remove from the heat, cover and let steep for 30 minutes. With a slotted spoon, lift the porcini out of the broth; chop coarsely and set aside. Strain the broth through a sieve lined with cheesecloth or a coffee filter and set aside.
Heat 2 tbs each of the oil and butter in one large or two medium saute pans or skillets over medium-high heat. When the oil and butter are hot, add the cremini mushrooms and saute, stirring often with a wooden spoon, until the mushrooms are softened and well browned, 6 to 8 minutes. Take the pan off the heat and transfer the cremini to a bowl.
Still over medium-high heat, melt the remaining 2 tbs butter in the pan and add the onion. Saute, scraping up any browned bits from the mushrooms in the bottom of the pan with the wooden spoon, until the onion is well softened and just begins to brown, 8 to 10 minutes. Transfer the onions to the bowl with the cremini. If the cooked-on juices in the pan look like they are burned, rinse out the pan.
Put the flour in a large bowl. Season the beef strips generously with salt and pepper and toss in the flour. Return the pan to medium-high heat and add the remaining 4 tbs oil. When the oil is hot, swirl to coat the pan and then add the beef, spreading it in a single layer and stirring with the wooden spoon so that it browns slightly on all sides, 1 to 2 minutes. Do not overcook it; it will cook more later. Be sure not to overcrowd the pan; work in batches if necessary. Take care not to burn the cooked-on flour and juices in the pan. These will flavour and thicken the sauce. When all the beef is sauteed, transfer it to the bowl with the cremini.
Pour the reserved porcini soaking broth, scraping the pan to dissolve all the cooked-on meat juices. Stir in the mustard, Worcestershire sauce, Tabasco, and creme fraiche. Simmer until the sauce thickens slightly and then add the porcini cremini, onions and beef, along with any accumulated juices. Reduce the heat to low and cook until everything has just heated through. Taste and adjust the seasonings. Serve over the egg noodles or fettuccine, sprinkled with the parsley.View more Beef recipes...