01 - Rinse lentils under cold water and place them in a pot with 3 cups of water; bring to a boil, then reduce to a simmer and cook for 20-25 minutes until tender but not mushy. Drain and set aside to cool.
02 - While lentils cook, dice celery, red bell pepper, shred carrots, and finely chop red onion. Set aside.
03 - In a small bowl, whisk together olive oil, lemon juice, apple cider vinegar, Dijon mustard, honey, salt, and pepper until emulsified.
04 - In a large bowl, combine cooled lentils, prepared vegetables, and chopped parsley. Pour dressing over the mixture and toss gently to coat evenly.
05 - Cover the salad and refrigerate for at least 1 hour to allow flavors to meld before serving.