To make the dressing, place the mustard, maple syrup, olive oil, lemon juice, and garlic into a large bowl and whisk to combine. Season with salt and pepper.

Using a mandoline, a sharp knife, or the slicing disk in a food processor, thinly slice the brussels sprouts, apple, and shallot and place into the bowl with the dressing. Toss well to combine.

When ready to eat, add the pecorino, almonds, and mint, and toss until all elements are well coated.