Ham Peas and Potatoes

3 lb. Red Potatoes
1 onion
1 ham steak
1/2 cup butter
1/2 cup flour
4 cups milk 
1/2 t. salt
1/2 t. pepper
1-2 cups frozen peas

Cut potatoes into 1-1/2 inch cubes boil until tender.  Set aside in fridge.  Saute chopped onion in the butter.  When soft add flour slowly and brown to make a roux.  Slowly add milk off the heat until smooth.  Add ham cut in cubes and any ham juices, salt and pepper.  Heat until boiling and thickened.  Boil for one minute.  Take off heat and add frozen peas and potatoes.  Keep warm on low.