In a small saucepan, heat vinegar and split vanilla bean over medium-high heat until reduced by half. About 10 to 15 minutes. Remove vanilla bean pods.
Preheat oven to 400°.
Cut off ends of the Brussels sprouts. If they're large, cut them in half.
Place the sprouts and pecans in a medium size bowl.
Toss with olive oil and the balsamic reduction. Season with salt.
Pour sprout mixture onto a baking sheet.
Roast for 25-35 minutes, or until tender. Make sure you stir them a couple of times during roasting.
