The vermouth, mustard and juniper berries provide a sweet - sharp flavor to this pot roast. Choose top round or a rump roast. Prepare it whole and slice at the end. Depending on its tenderness, count 2 - 3 hours.
Rub the large piece of meat with salt and pepper, then spread a thin layer of mustard (strong mustard will give a greater spicy flavor at the end) onto it. Set this spiced roast aside to soak in the flavors while you do the next steps.
Roughly chop the onion. Wash the celery, and cut it into finger length slices. Slice the thick bacon into 1/4" strips.
Heat a heavy stewing pot, add sunflower oil, and sear the roast on all sides. Remove the meat to a dish. Brown the onions, celery and bacon in the pot that you seared the meat inches Reduce heat so nothing burns.
Pour the dry vermouth (I use Noilly Prat) into the stew pot. Add the bay leaf, the peppercorns and juniper berries, then lower the meat into the pot. Cover, and set the heat to its lowest level to slow cook this.
After an hour, turn the meat. If the liquid reduced too much, add a cup of water. After another hour, the meat should be tender. If not, cook a while longer. You want it to be tender, but firm enough to slice.
When ready, take the meat out, and wrap it in aluminum foil.
Now, use a slotted spoon or small colander to strain the vegetables. Discard them. Now, strain the sauce through a fine sieve. Reduce this strained sauce in a saucepan, and reduce it until it has the consistency of a light gravy. Season with salt, pepper, and mustard, if desired.
Slice the roast into thick serving pieces, and warm the slices in the sauce you have produced. Serve when warmed through. Serve with boiled or mashed potatoes and mushrooms, carrots and/or peas.