I don't know about a New England pot roast, just plain ol' pot roast.

I use a Dutch oven (has a well-fitted lid) or sometimes do a pot roast in the crock pot (after browning it in the pan). I brown it in oil like canola oil; butter can burn. I don't put in quite so much water as Kendall does, but if you cook it fairly low, just above the simmer, the juices from the meat as it cooks add to the liquid in the pan. After the meat is mostly browned I drop in a quartered onion to brown for a couple of minutes before I add the liquid and a bay leaf. When it is cooked enough to add veggies, I add more onions with the potatoes and carrots because the first batch have given flavor and liquid to the roast but have cooked down to nothing. They help thicken it a little.

Season it with salt, fresh-ground pepper, and sometimes I pour a little red wine (1/2 cup or so) into the juices near the end of cooking. After you take out the roast you can thicken the juice just a little (~1/4 cup of flour mixed into 1/2 cup of water and slowly added and mixed into the pot juices a couple of minutes before serving).

SRS