Cook the pasta according to package directions, omitting salt and fat. Drain; toss with butter and 1/4 teaspoon salt.
While the pasta cooks, heat 1 1/2 teaspoons oil in a large nonstick skillet over medium-high heat.
Place flour in a shallow dish. Sprinkle pork with 1/2 teaspoon salt and pepper; dredge pork in flour. Add half of pork to pan; cook 2 minutes on each side or until browned. Remove pork from pan. Repeat procedure with remaining 1 1/2 teaspoons oil and pork.
Add shallots and mushrooms to pan; sauté 2 minutes. Add broth and wine; bring to a boil. Reduce heat, and simmer 2 minutes, stirring occasionally. Return pork to pan; cover and simmer for 3 minutes or until pork is done. Serve the pork mixture over pasta. Sprinkle with onions.