Inevitably, some of the leaves come off the sprouts as they roast, and they become delectably charred in the heat of the oven. Don’t discard them; they taste sublime.
Preheat oven to 375 degrees F. Remove any wilted outer leaves from the sprouts. If the sprouts are large, cut each in half; if small, leave whole and put two slits into the bottom. In a mixing bowl, toss the sprouts with the sliced onion and oil. Spread in a medium-large, shallow casserole and scatter the bacon over the spouts. Season with salt and pepper to taste, and sprinkle with a teaspoon or two of water. Cover loosely with foil and bake for 15 minutes. Uncover and roast for 25 to 30 minutes, or until tender, stirring every 10 minutes. Transfer to a serving dish.
Preparation tip: This dish tastes best when freshly cooked and piping hot, not reheated. If you don’t have two ovens, get everything ready to go and put this in the minute the turkey or roast comes out. Boost the heat to 400 degrees F and roast, uncovered, for about 25 minutes. That will allow time for the meat to sit and everyone to gather before it’s carved.