Heat a small skillet on high. When hot add the butter. Swirl butter in skillet to melt. Add filets and sauti until seared brown on both sides (4 5 minutes per side for 3/4 inch thickness, medium rare). Remove filets to a plate and tent with foil. Add shallots and mustard, and sauti 1 minute, do not brown. Deglaze pan with Madeira. Reduce heat to medium low and add heavy cream. Heat for 1 minute, add peppercorns. Crush peppercorns gently with back of a wooden spoon to release flavor. Season to taste with salt and white pepper. Raise heat and cook until just thickened. Serve filets with sauce spooned over top and garnish with sautied mushroom caps. Serve with new potatoes roasted with rosemary, garlic and parsley, and buttered baby carrots. NOTES: You can use this recipe for a whole or partial filet if you like. Cook a whole filet in the oven, or in a skillet if it will fit. Make sauce (increasing quantities as desired) using any bits scrapped off the roasting pan and a few tablespoons of strong beef stock. Slice beef on the bias, place on a platter and pour sauce over