RENDER bacon until slightly browned, in large sauté pan on medium-high heat, a few minutes. Add the Brussels sprouts and cook until browned on at least one side, about 3 minutes.
ADD the shallots and open up their fragrance, about 1 minute. Add the vinegar, remove from heat, and toss. Return the pan to the heat until the Brussels sprouts are just tender, about 3 to 5 minutes. Remove from heat.
ADD the frisée, apples, almonds and extra-virgin olive oil and toss. Season to taste with salt and pepper. Plate or eat right out of the pan.