In a large mixing bowl, combine the mayonnaise, sour cream, Dijon mustard, lemon juice, garlic powder, salt, and pepper. Whisk until the dressing is smooth and fully combined.
Add the shredded plant-based chicken, chopped celery, diced red onion, and fresh dill to the bowl with the dressing. Use a large spoon or spatula to gently fold all ingredients together until everything is evenly coated.
Taste the salad and adjust seasonings if desired, adding more salt, pepper, or lemon juice to your preference.
For the best flavor, cover the bowl with plastic wrap and refrigerate the salad for at least 30 minutes to allow the flavors to meld.
Just before serving, slice the croissant rolls in half horizontally. Spoon a generous portion of the chilled salad onto the bottom half of each croissant, then replace the top half.
Notes
For the best flavor, refrigerate the salad for at least 30 minutes to allow the flavors to meld.