For the dressing. Reduce the apple cider by boiling it down to 1/4 of a cup. The cider will have become very sweet and syrupy.
Whisk in the brown mustard, apple cider vinegar and salt. Add pepper to your taste. Set the dressing aside. You won't be using all the dressing.
Take the 2 cups of sliced Fennel and put it on a baking sheet lined with parchment paper. Drizzle some oil[ less than 1/2 tablespoon should do] Sprinkle some salt and roast in preheated 375 degree oven for 25-30 minute, turning once after 20 minutes. When it is nicely caramalized, remove and set aside.
Mix the 1/2 cup of apple and the 1/2 cup of fennel matchsticks and marinade it in 1 tablespoon of the reduced apple cider dressing. Taste and add salt and pepper to your taste. Let it marinade for atleast 15 minutes..
Now assemble the salad. Put the marinaded salad on to a serving dish. Top with the roasted fennel. Add the shaved cheddar. Drizzle some of the salad dressing around the salad. Garnish with fennel fronds if using.