5 pounds Brussels sprouts, trimmed and halved
12 ounces thick-sliced bacon, cut into pieces
1⁄2 cup diced red onion
1⁄4 cup honey
3 tablespoons apple cider vinegar
1⁄4 teaspoon coarse salt
1⁄4 teaspoon freshly ground black pepper
Preheat oven to 400°. Position oven racks in top and bottom thirds of oven. In 2 large rimmed baking pans, spread Brussels sprouts in a single layer.
In a large skillet, cook bacon over medium heat until crisp. Remove bacon and drain on paper towels, reserving 1⁄4 cup drippings in skillet.
Add onion to hot drippings in skillet and cook, stirring constantly, for 6 to 8 minutes or until tender. Remove from heat; add half of onions and bacon drippings to each pan of Brussels sprouts. Toss well and spread in a single layer.
Bake for 20 minutes. In a small bowl, combine honey and vinegar. Remove pans from oven; stir half of honey mixture into each pan of Brussels sprouts and spread in a single layer. Rotate position of pans on oven racks. Bake for 5 minutes or until Brussels sprouts are browned and just tender. Sprinkle with salt and pepper. Toss with bacon just before serving.
To make ahead: Trim and halve Brussels sprouts up to 1 day ahead and store in a zip-top plastic bag in the refrigerator. Cook bacon; refrigerate bacon and drippings separately. Remove from refrigerator and proceed with recipe beginning with Step 3.