Scrub the beets lightly and boil them for 35 minutes until barely tender; Drain under cold water, peel, then slice into 1/4 inch pieces.
Melt the butter and cook the shallots for 4 minutes over medium heat.
Turn the heat down and stir in the flour; Cook for 2 minutes stirring often.
Add the stock, mustard and cream; Cook for a few minutes until thick.
Combine with the beets and cook for a few minutes until it is warm.
Add salt and pepper to taste - Serve with parsley sprinkled on top.