In a large skillet over medium heat, add bacon. Cook for 10 minutes, until bacon is brown and very crispy. Transfer bacon to a paper towel lined plate and discard all but 1/2 tablespoon of bacon fat from skillet.
Reduce heat to low. To the skillet, add the chicken, broccoli and Brussels sprouts and salt and pepper. Cook for 10 minutes, stirring occasionally, until the chicken is cooked through and the vegetables are tender.
In a large bowl, layer the spinach, shallot, bacon and vegetable mix.
In a small bowl, whisk the remaining 3 ingredients and sea salt and freshly ground black pepper to taste. Pour the dressing over the salad. Toss and serve.