1/4 c. butter
1 c. chopped onion
3 tbsp. flour
2 c. milk
1/2 tsp. salt
1/4 tsp. pepper
1 1/2 tbsp. Dijon mustard
2 c. shredded Swiss cheese
2 lbs. potatoes, peeled, cooked & thinly sliced
1 lb. Kielbasa or Polish sausage, cut in 1/4 inch slices
Chopped parsley (optional)

Melt butter in medium saucepan. Add onion and saute until tender. With wire whisk blend in flour. Slowly add milk, stirring until mixture comes to a boil and thickens. Add salt, pepper and mustard. Remove from heat and stir in 1 1/2 cups cheese.

In greased 12 x 8 inch baking dish, arrange, alternating slices of half the potatoes and sausage in a single layer. Pour on half the sausage, then layer the remaining potatoes and sausage. Pour on remaining sauce; sprinkle with remaining cheese. (Can be made ahead to this point. Cover with plastic wrap and refrigerate up to 24 hours. Let stand at room temperature 30 minutes before baking.)

Preheat oven to 350 degrees. Bake, uncovered, 45 to 60 minutes or until top browns and center is heated through. Sprinkle with chopped parsley, if desired. Makes 8 servings, about 525 calories each.