In a medium bowl, toss Brussels Sprouts, olive oil, mustard, garlic, salt and pepper to coat sprouts evenly.
Line evenly on a parchment lined baking sheet.
Place in oven to roast for about 20-25 minutes or until browned to liking.
Toss pecans in the leftover olive oil from the sprouts or add about 1 tsp more if needs.
Add the pecans to the roasting Brussels Sprouts in the last 3-5 minutes to lightly toast.
While sprouts are roasting, in a small sauce pan, combine balsamic vinegar, maple and sea salt if desired and set stove to medium heat.
Allow the mixture to come to a boil and stir frequently for about 3-5 minutes.
When the mixture begins to reduce and thicken slightly, remove it from the heat and allow to cool for a few minutes before drizzling over Brussels Sprouts. Save any leftover glaze in a sealed container in the refrigerator. It's great over other veggies and so much more!
Halfway through the roasting, I typically toss the sprouts around a bit so they brown more evenly.