Lamb Stew and figuring out "done-ness"

Much appreciated, that's exactly what I was trying to do without understanding the temperate ranges clearly. I have also not been "resting" my braise to allow it to come down to 125 while still in the liquid, and I will absolutely try that. Thanks again

This is one of the few times I will disagree with my friend and esteemed colleague Pierino. I will argue that the oven provides even heat from all directions plus it's got a thermostat which makes for easy, repeatable temperature control. You can do it either way but here's my take:

There are reasons for braising at higher temperatures but above 250F the braising liquid will reach a boil unless the pot is left uncovered. That's not low and slow.

The basics behind the technique: Enzymatic action peaks right before the enzymes denature, between 120F and 130F. The longer the meat stays close to, but under that temperature, the more tender and flavorful it will become.

However, conversion of collagen (connective tissue) to gelatin doesn't begin until the meat reaches an internal temperature of around 140F. The longer the roast exceeds 140F, the more tender it will become.

To give a tough cut of meat maximum advantage, sear then set the oven to 200F, lid ajar, for 2 hours (vessel target temperature = 120F). Then cover and raise the oven to 250F and allow the roast to slowly come up past the 140 mark and finish cooking. Allow to cool for at least 30 min. or, ideally, down to 125F in the braising liquid, some of which will be reabsorbed in the process.

Or just set the oven between 225 and 250F from the beginning and walk away.

Don't confuse undercooked with overcooked. There's a point midway where the meat will toughen but later it will begin to fall apart as the connective tissue is broken down.

Makes sense to me, thanks again for the comments and feedback.

Thanks all for the comments, if I run the oven at 350, won't the whole thing come to a boil in the oven? If I want it to just simmer away for a couple of hours, what would you think about keeping the oven really low.... say 250-ish? or is it just going to take an age?

Well, when you got to the "pull the meat apart" part you arrived at the right answer. Using a pair of forks the meat should separate from the bone easily. Don't let your braise come to a full boil because if you do it will become tough and unchewable (unless you happen to be English). Braising requires low heat (a simmer), time and patience.

I have made many a lamb shank and although I don't have a scientific formula I can tell you that in my experience lamb shanks require significant cooking time to get them fall off the bone tender. They are a bit tough by nature, I make 4 shanks at a time they vary in weight but are usually a little over a pound each, braising IMHO is the best way to achieve a tender shank. I start on the stove top finish in the oven set at 350 degrees and I braise for about 3 hours. I have never over cooked a shank but have undercooked and thats not pleasant. I always make sure the meat is completely covered in stock and wine, bring to a boil on stove top, cover and place in the oven for the rest of the cooking time. It's done when the meat pulls away from the bone easily with a fork. I usually start checking after 2 1/2 hours.