Hi Chris, as long as you can fit all the ingredients without going over the fill line, you should be able to double the recipe with no problem. The set cook time won’t change, but the pot will take longer to come to and release pressure so it will cook longer overall.

Hi Sara, yes, I think it would. I would go with a butt roast (which, ironically, usually comes from the shoulder) instead of a loin roast though so you have the extra fat to keep it from being too dry.