This recipe is from Tyler Florence, a side to his Prime Rib recipe. I've made it a few times and substituted 1 package frozen pearl onions, thawed, for the red onions, and added medium sized button mushrooms half way through the cooking time. I was never sure just how much a 'half bunch' of fresh thyme was, (and rarely have it on hand) so I used a little less than a tblsp of dried thyme. I also doubled the sauce recipe, due to the size of the onion pkg, and addition of the mushrooms. Delicious.