Using a food processor, mandoline, or a sharp knife, shred the Brussels sprouts thinly. Rinse the shredded Brussels sprouts and transfer to a large salad bowl.
1 lb Brussels sprouts
In a small bowl, whisk together the olive oil, apple cider vinegar, maple syrup, dijon mustard, salt, and pepper until well combined and emulsified.
3 tbsp olive oil, 2 tbsp apple cider vinegar, 1 tbsp maple syrup, 1 tbsp Dijon mustard, ¼ tsp salt, ¼ tsp pepper
To the shredded Brussels sprouts, add the walnuts, apples, and red onion. Toss everything together to combine.
½ cup walnuts, 1 apple, ¼ cup red onion
Pour the dressing over the salad and toss until everything is evenly coated.
Let the salad sit for about 10 minutes before serving to allow the flavors to meld together.