1. Cook pasta according to package directions.
2. Heat oil in a medium skillet over low and saute mushrooms until tender (5-8 minutes). Add the peas, cover, and cook until tender (2-3 minutes).
3. In small bowl, whisk together milk and cheeses. Remove pan from heat and stir in milk mixture, using residual heat to warm the sauce.
4. Toss with pasta to serve.