Grandma Jeanne's Mustard Potatoes

 This recipe has been in the family a long time- my grandma Jeanne made these. They go great with ham.

Mustard potatoes

2 1/2 lbs potatoes, peeled and cubed in about 3/4-1 inch cubes
1 med onion, chopped
5 Tbsp butter
2 Tbsp flour
1 tsp salt, pepper to taste
1 can undiluted consommé (for example, Campbell's brand)
1/4 prepared yellow mustard

Boil cubed potatoes until tender, about 15 min. Drain. Meanwhile, sauté onions in butter until tender, then add flour and cook a few minutes. Whisk in undiluted soup, mustard, salt and pepper, then add potatoes. Place in a greased casserole dish and bake at 375 for 30-40 minutes.