1 1/2 pounds Brussels sprouts (about 5 cups), stems trimmed and outer leaves removed
1/4 pound double-smoked slab bacon or other smoked bacon, cut into lardons (1/4-by-3/4-inch rectangles)
2 cups pearl onions, peeled
10 chestnuts, roasted, peeled, and quartered
1 3/4 cups low-sodium chicken broth
1 tablespoon unsalted butter
1 1/2 teaspoons fresh thyme leaves
Fill a large pot with water and bring to a boil over high heat. Add enough salt until the water is salty tasting. Prepare an ice water bath by filling a bowl halfway with ice and water; set aside. Cook Brussels sprouts in boiling water until crisp-tender, about 4 to 5 minutes; they will still have some bite to them. Drain sprouts and place in ice bath.
When cool, remove sprouts from ice water, halve lengthwise, and set aside. Place a large sauté pan over medium heat. Add bacon in a single layer and cook over medium heat until fat is rendered and bacon is golden brown, about 10 minutes. Remove bacon with a slotted spoon and set aside; reserve pan drippings.
Add onions to the pan and reduce heat to low. Cook onions, stirring occasionally, until they turn a deep golden color, about 8 to 10 minutes. Add chestnuts and cook, stirring occasionally, until thoroughly heated and well coated with bacon fat, about 2 minutes.
Increase heat to high and add bacon and Brussels sprouts and stir well. Add chicken broth and cover. The contents will quickly come to a boil. Reduce heat to low and cook until Brussels sprouts are heated through. Stir in butter and season with salt and pepper. Sprinkle with thyme and serve.