chicken tetrazzini bake

Ingredients

• 1/2 cup onions, sliced
• 1/4 cup butter
• 1/4 cup flour
• 1/2 teaspoon salt
• 1/2 teaspoon sage, ground
• 1/4 teaspoon pepper
• 2 cups chicken broth
• 1 cup milk
• 1 jar mushrooms, sliced and drained
• 3 cups chicken, cooked and cubed
• 1/2 cup chopped parsley
• 1/3 cup grated parmesan cheese
• 1 package spaghetti, cooked
• 1 jar pimentos, 4 ounces drained
• 1/2 cup shredded swiss cheese