In a large pan on medium-high, saute bacon and caraway seeds 2 minutes. Add onion, thyme, salt, and pepper, cook, stirring occasionally, until onion begins to brown and bacon is crisp, about 8 minutes. Remove from heat. Add vinegar and scrape up any browned bits. Set aside to cool.
Meanwhile, bring a pot of salted water to a boil. Fill a large bowl with ice water. Blanch sprouts in boiling water 6-7 minutes, until tender but still crisp. Drain and transfer to ice bath. When cool drain again and toss thoroughly with cooled bacon mixture.
Transfer to a resealable container and refrigerate until 2 hours before serving.