Preheat the oven to 400°. Line a baking sheet with parchment paper or foil.
Trim the stems of the Brussel sprouts and remove any discolored outer leaves. Slice them in half lengthwise.
In a large bowl, whisk together the olive oil, brown sugar, and Dijon mustard.
Add the Brussel sprouts and cranberries and toss to coat them evenly with the brown sugar mixture.
Spread evenly on the prepared baking sheet. Sprinkle with salt and pepper. Roast in the center of the oven 15 -20 minutes, until sprouts are tender and beginning to caramelize.
Return to a bowl and add the pecans. Toss to combine and serve.
Notes
Use small Brussels sprouts: Smaller sprouts tend to be sweeter and more flavorful. Plus, they crisp up better. If you have the option, opt for small, tightly closed sprouts.
Watch your oven: All ovens vary slightly, so keep an eye on the Brussels sprouts as they roast to make sure they don’t burn. You may want to invest in an oven thermometer to double-check the accuracy of your oven.
Roast flat side down: For the crispiest, most caramelized texture, make sure you cook Brussels sprouts flat side down.
Don’t crowd the pan: To prevent a steamed Brussels sprouts texture, leave ample room between each one on your baking pan. If need be, use two baking pans.
Dry after washing: Thoroughly dry the Brussels sprouts after washing them. If you skip this step, they won’t crisp up as nicely.
Don’t move them around: It may be tempting to move the sprouts around and check on them, but the less you move them, the more charred they will turn out.