Prepare the dressing: In a bowl, combine apple cider vinegar, maple syrup, thyme, and grainy mustard.

Slowly whisk in olive oil until the dressing is emulsified and well combined.

Alternatively, blend the dressing ingredients in a blender until smooth.

Prepare the salad: Chop, wash, and spin dry the lettuce.

Place the lettuce in a large salad bowl.

Core and thinly slice the apple.

Thinly slice the red onion.

Shred the cheddar cheese.

Add the sliced apple, red onion, shredded cheddar cheese, dried cranberries, and toasted walnuts to the salad bowl.

Toss the salad with the maple mustard vinaigrette.

Serve immediately.