Wash and dry the fresh produce. Heat a medium pot of salted water to boiling on high. Medium dice the potatoes. Cut off and discard the stem ends of the Brussels sprouts. Pick off and reserve the Brussels sprout leaves; thinly slice the lighter cores. Thinly slice the celery crosswise. Quarter and deseed the lemon. Peel the shallot and mince to get 2tablespoons (you may have extra). In a bowl, combine the shallot, mustard and the juice of 2 lemon wedges. Slowly whisk in 2 tablespoons of olive oil until well combined; season with salt and pepper to taste.
Add the potato to the pot of boiling water and cook 13 to 15 minutes, or until tender when pierced with a fork. Turn off the heat. Drain thoroughly and return to the pot.
While the potato cooks, in a medium pan(nonstick, if you have one), heat 2 teaspoons of olive oil on medium-high until hot. Add the Brussels sprouts; season with salt and pepper. Cook, stirring occasionally, 2 to 3 minutes, or until lightly browned and slightly softened. Transfer to a bow.
To the pot of cooked potato, add the cooked Brussels sprouts, celery, cheese and enough of the vinaigrette to coat the salad (you may have extra vinaigrette). Stir to thoroughly combine; season with salt and pepper to taste. Enjoy!