Source: What Would Cathy Eat? http://www.whatwouldcathyeat.com/2011/11/roasted-brussels-sprouts-with-sherry-mustard-vinaigrette/
2 pounds Brussels sprouts, trimmed
4 tablespoons extra virgin olive oil, divided
2 tablespoons finely minced shallot
2-3 cloves garlic, minced
1/2 cup aged sherry vinegar
1 teaspoon fresh thyme
1 tablespoon Dijon mustard
1 tablespoon coarse-ground Dijon mustard
2 tablespoons agave nectar
Freshly ground black pepper to taste
Heat the oven to 400 degrees.
Heat 1 tablespoon of the olive oil in a small skillet or saucepan. Add shallot and garlic and stir for 30 seconds.
Stir in vinegar, thyme, mustard and agave. Simmer on medium heat until reduced by about half (about 4 minutes).
Remove from heat and whisk in 2 tablespoons of olive oil. Season with pepper. Pour the dressing into a serving bowl.
Toss the brussel sprouts with the remaining tablespoon of olive oil and place on a large baking sheet. Roast the brussels sprouts until very dark and just tender, about 40 minutes.
Toss with the vinaigrette and serve warm or at room temperature.