Bennigan's Potato Soup

Source: Houston Chronicle.

NOTE: If you do not have soup base available, please use a piece of ham or chicken for this.

1 tablespoon ham base
1 quart chicken base
6 tablespoons margarine, divided
1/4 pound yellow onion, diced
1 pound potatoes, diced
3/4 teaspoon ground black pepper
1 1/2 ounces flour
1 cup milk
Chopped parsley for garnish

Combine ham and chicken bases in a saucepan and whish until no lumps appear.

Melt 3 tablespoons margarine in a stockpot and saut