Scalloped Tuna - cooking recipe

Ingredients

4 c. thinly sliced potatoes
3 Tbsp. butter
1/4 c. flour
2 Tbsp. prepared mustard
1 tsp. salt
1/8 tsp. pepper
2 c. milk
1 (7 oz.) can solid tuna
1 c. thinly sliced onion

Preparation

Boil potatoes in salted water for 10 minutes.
Melt butter; blend in flour, seasonings and milk, gradually.
Bring to a boil.