Preheat the oven 350 degrees F. Place the beef in a bowl and season with salt and pepper. Add the flour and toss to coat. Place the oil in a large skillet set over medium-high.
When hot, cook the beef, in batches, until nicely browned, and then set in a 9" x 13"casserole. Add the leek and shallot to the skillet and cook 3 minutes. Add the remaining ingredients, except parsley, bring to a simmer, and then pour over the beef. Cover and cook in the oven 75 minutes, or until the beef is tender. Adjust seasoning to taste. Sprinkle servings of the beef with parsley.
Note: Green peppercorns are sold in jars in the aisle where pickles are sold.