Preheat the oven to 375 degrees F. Arrange one oven rack in the lower third of the oven and one in the upper third. In a small bowl, combine thyme, salt and pepper. Set 2 teaspoons of herb mixture aside (or 5 teaspoons if using fresh thyme), then sprinkle remaining mixture over all sides of the pork. Place pork fat side up in a shallow roasting pan, and then place pan on the lower rack in the oven; roast until the internal temperature reaches between 145 degrees F (medium rare) to 160 degrees F. (medium), 1 1/2 to 1 3/4 hours. About 30 minutes before pork is done, in a large bowl, combine cauliflower, sliced shallots and reserved herb mixture. Transfer to a rimmed baking sheet and scatter bacon on top. Place baking sheet on the upper rack in the oven, and roast until cauliflower is tender and bacon is browned, about 40 minutes.
Meanwhile, make the Chardonnay Butter Sauce: In a medium saucepan over medium-high heat, combine wine, cream and diced shallots and bring to a boil. Cook; stirring occasionally, until reduced to 2/3 cup, about 10 minutes (adjust heat to avoid boiling over). Remove from heat and whisk in butter, 2 or 3 pieces at a time, waiting until the pieces are melted before adding more. Add salt and pepper to taste. Cover to keep warm, set aside.
Remove the roast from oven and let rest 10 minutes (the cauliflower will continue cooking; it should be done about when the roast is finished resting).
Slice the roast between the rib bones. Serve drizzled with the pan juices, and with the cauliflower and sauce on the side.