Step 1Heat the oven to 400 degrees.
Step 2In a large bowl, combine the Brussels sprouts, ham, 6 tablespoons oil, 1 teaspoon salt and several grinds of black pepper, or to taste. Spread the sprouts in a single layer on a foil-lined rimmed baking sheet. Tuck in the sliced pears right before roasting.
Step 3Roast, uncovered, until the sprouts are caramelized and tender, 30 to 40 minutes, tossing every 15 minutes or so for even coloring.
Step 4While the sprouts are roasting, in a small bowl, whisk together the remaining 3 tablespoons oil along with the vinegar, syrup and mustard.
Step 5Remove the sprouts from the oven and drizzle over the sauce, tossing to combine. Spoon the vegetables into a serving dish to serve.