To prepare dressing, combine 1/2 cup apple chips with apple juice and cider vinegar in a small bowl. Set aside to soften.

In a medium skillet, cook bacon in olive oil until crisp. Remove bacon from skillet with slotted spoon.

Add shallot to pan and cook until softened. Whisk in mustard, pepper and apple mixture to pan and cook for 1-2 minutes until heated through.

Place warm dressing in a large bowl.

Add spinach, red onion and celery. Toss well to coat with dressing.

Divide salad between 4 plates, topping each portion with blue cheese, bacon and apple chips. Serve immediately.