Brussels Sprouts, Roasted with Pancetta

Ingredients

• 1 1/2 lb. brussels sprouts, trimmed and cut in half through the core
• 4 ounces pancetta, sliced 1/4 inch thick
• 1/4 cup good olive oil
• 1 1/2 teaspoons kosher salt, plus more, to taste
• 1/2 teaspoon freshly ground pepper, plus more, to taste
• 1 tablespoon syrupy balsamic vinegar (see note)