Brussels Sprouts Gratin Recipe My GoTo Cheesy Holiday Side

Ingredients

• 1.5 lb Brussels sprouts (about 700 g), trimmed and halved (large ones quartered)
• 1 tablespoon (15 ml) olive oil
• Salt and freshly ground black pepper
• 2 tablespoons (28 g) unsalted butter
• 1 small shallot, finely minced (about 2 tablespoons / 20 g) — optional but recommended
• 1 garlic clove, minced (optional)
• 2 tablespoons (16 g) all-purpose flour
• 1 cup (240 ml) whole milk
• 1/2 cup (120 ml) heavy cream
• 1 teaspoon Dijon mustard
• Pinch freshly grated nutmeg
• 1/2 teaspoon kosher salt (adjust to taste)
• 1/4 teaspoon freshly ground black pepper
• 1 1/2 cups (150 g) grated Gruyère or Comté (or sharp white cheddar) — divided (about 1¼ cup for sauce + ¼ cup for topping)
• 1/2 cup (50 g) freshly grated Parmesan or Pecorino
• 1/2 cup (50 g) panko breadcrumbs
• 1 tablespoon (14 g) unsalted butter, melted (to toss with panko)
• Zest of 1/2 lemon (optional, for brightness)
• Optional garnish: chopped fresh parsley or chives
• Optional add-ins: 4 slices bacon, cooked crisp and crumbled (or 4 oz / 115 g pancetta, rendered)
• Optional: 1/4 teaspoon red pepper flakes for a touch of heat