Shave or finely slice the Brussels sprouts and set in large mixing bowl.
Cook your bacon or pancetta on the stovetop according to package directions. When pancetta is crisp and cooked, remove from pan, but keep the fat to toast your nuts and raisins together. Over medium-low heat in the same pan with the pancetta fat, add your chopped walnuts and raisins.
Cook until nuts are toasted and raisins are soft and rehydrated—5 minutes.
Pour hot pancetta and walnuts into the sprouts and toss. This will allow the leaves to wilt and soften ever so slightly.
In a small bowl, combine olive oil, vinegar, dijon, honey, garlic, and salt to taste.
Add the dressing, celery, and apples to the Brussel sprouts. Toss to combine, and salt to taste. Serve warmed or cool.