Melt margarine in large skillet, saute onions, blend in flour until
smooth. Add broth and milk, stir until smooth. Add yellow
cheese, salt, pepper, and lemon juice. Stir until cheese melts.
Lower heat and simmer uncovered for 10-15 mins.
While simmering, cook vermicelli, drain. Add pasta to sauce
with cheese. Spoon into greased casserole dish. Sprinkle
top with cheese.
Bake at 400º for 20-30 mins.