Heat 1 tablespoon of vegetable oil in a large pan over medium-high heat. Working in batches so as not to overcrowd the pan, add about half the mushrooms and sauté until lightly browned, 5 to 6 minutes. Season to taste with salt and pepper. Transfer to a bowl, add another tablespoon of oil and repeat the process with the remaining mushrooms.
Reduce the heat to medium and add another tablespoon of oil to the pan. Add the onions and garlic and sauté until the onions are soft and translucent, 3 to 4 minutes. Add to the reserved mushrooms and set aside.
Put a large pot of salted water on to boil for the noodles.
Combine the flour, salt, pepper, allspice and cloves in a shallow dish. Trim any excess fat and silver skin from the pork tenderloins. Slice each in half lengthwise, then cut crosswise into 3/8-inch slices. Reserve about 1 tablespoon of the flour for later use, then dredge the pork, a few pieces at a time, in the seasoned flour.
Add another tablespoon of oil to the pan and heat on medium-high. Add about half of the pork and cook, turning with tongs, just until lightly browned on both sides, about 3 minutes total. Transfer to a plate, add more oil, cook the remaining pork and set aside.
Return the mushroom-onion mixture to the pan, sprinkle with the reserved flour and combine to coat the vegetables. Cook for 2 minutes, stirring frequently, then add all but 1/4 cup of the chicken broth. Bring the mixture to a boil and cook, stirring frequently, until the sauce has thickened, about 3 minutes. In a separate bowl, whisk together the reserved chicken broth with 1/2 cup of the sour cream and add to the mushrooms and sauce. Combine thoroughly and cook until heated through.
Add the pork to the pan, turning the pieces several times to coat with the sauce and continue cooking 2 to 3 minutes until the sauce is thick and creamy. If you feel the sauce is too thick, add a bit more broth or plain water at this point. Taste and adjust the seasoning if necessary. Remove from the heat and keep warm.
Cook the egg noodles according to the package directions. Drain, toss with the butter and season with salt and pepper.
To serve, plate a portion of egg noodles and top with pork and mushrooms. Spoon some sauce over the top, add a small dollop of sour cream and sprinkle with a pinch of allspice for garnish.