In a mixing bowl or salad dressing container: Add shallots and apple cider vinegar. Let sit for about 2 minutes. Add the remaining salad dressing ingredients and whisk until well blended.
In a large mixing bowl: add Brussels sprouts, chopped apple, cooked bacon, chopped walnuts, Pecorino Romano Cheese, spearmint leaves and the homemade shallot vinaigrette salad dressing (about 5 tbsp). Mix well.
Optional: adjust with salt/pepper, extra salad dressing, or 1 tablespoon fresh lemon juice for rich and intense flavor.
Serve immediately.
Notes
To cook bacon on microwave: Place 2 sheets of paper towel on a plate, lay up 2 thick bacon slices on the paper towels and cook on high heat for about 2-3 minutes.