|Source||Jean Ross (2002)|
Preheat oven to 350 degrees. Cook beans until just tender; drain. Melt butter. Add onion and brown lightly. Stir in flour, mustard, salt and pepper. Gradually add milk; cook and stir until thickened. Add cheese and stir until melted. Combine sauce and beans. Pour into greased 1 1/2-quart casserole. Sprinkle with cashews. Bake about 20 minutes.