I don't think I've ever seen a brisket more than about 6-7 lbs. You'll
probably have to get a couple like that to meet the required weight.
If you don't have a large enough covered roasting pan to hold all that
meat at once, you could use a large oven bag or two, resting on a
cookie sheet or two.

For brisket in the oven, I season the meat with salt and pepper at
least, adding other rubs and seasonings as mood dictates. Instead of
on the stovetop, I like to brown the brisket on the grill outdoors if I
can, with lots of wood chunks/chips to get as much smoke onto the meat
as I can in that fairly short time.

The most important ingredient other than the meat, imo, is the onions,
as you mentioned. I slice up LOTS of onions, enough to provide a bed
for the brisket(s) to rest on, plus enough to cover completely. I'll
add a cup and a half or a bit more of liquid to the pan or bag, beer if
I have it on hand (non-alcoholic is fine), or just water with some
sherry wine and cider vinegar added, also depending on mood. Plan on
at least 3 hours cooking time at 325 deg.

De-grease the drippings remaining in the pan or bag by whatever means
you normally use, then reduce them for a sauce for the meat. This
sauce can be flavored in any number of ways with herbs, spices, juices,
etc. to taste, as it's being reduced. Any extra drippings can be
frozen for future use in soups, stews or whatever. If you use an oven
bag, you may find that the onions will brown up nicely, and can be
served with the meat and sauce. This doesn't seem to happen as much in
a covered roasting pan.

Bob
===========================
Michael "Dog3" Lonergan wrote:
> Steven's sister is doing Thanksgiving this year. It was officially decided
> this morning Yippee!!! We don't have to do it this year. However, we have
> to bring a large brisket and 3 types of pies. There will be about 25 people
> there. The SIL will be doing the turkey and all the fixings but several
> people do not like turkey. Soooo, it was decided a brisket was in order.
> I've done small briskets many times but the one this time will be most
> likely 10 pounds or a bit larger. I've never done one that large. I do not
> want to smoke it, I want to do it in the oven. I can find dozens of
> recipes online but I'm mostly interested in suggestion for doing a large
> brisket in the oven. I'll also be smothering the brisket with onions which
> should make a terrific onion gravy. How do all you cooks do big briskets?
>
> We also have to bring a couple each of cherry, apple and pumpkin pies.
> I'll make 3 pumpkin pies. Pumpkin pie is about the only thing I can bake
> from scratch and have it turn out well. I'll buy a Dutch apple, regular
> apple and 2 cherry pies from the bakery.
>
> Ob lunch:
>
> Had some left over chili. Boiled up some elbow macaroni, put the chili on
> top, microwaved and grated some fresh Asiago on top.
>
> Michael
>
> --
> "I come from a family where gravy is considered a beverage."
> - Erma Bombeck