First, I trimmed the stems and removed any loose, ragged outer leaves from the Brussels sprouts. Then I cut them in half—if any were very large I quartered them so all pieces were a similar size, ensuring even roasting.
Next, I preheated the oven to 425°F (around 220°C) and placed a rack in the middle position. On a foil-lined baking sheet I tossed the sprouts with 2 tablespoons of the olive oil, the salt, and the pepper. Then I roasted them and stirred once halfway through, until they were tender and golden brown (about 20 minutes).
Once the sprouts were roasted, I drizzled the remaining tablespoon of olive oil, the balsamic vinegar, and the honey over them. Then I tossed everything to coat evenly, tasted and adjusted seasoning if needed, and served immediately.