Brussels, Beemster, and Bacon Gratin

Adapted from a recipe by Tara Matarazza at Serious Eats. Beemster is a Gouda-style cheese similar to aged Goudas; if you can't find it, a 5-year-aged Gouda is a reasonable substitute. The regular Gouda is used for creaminess; if you use the aged Gouda, consider replacing the regular Gouda with Fontina or Havarti.

• Ready In: 55 mins
• Serves: 4

Ingredients

• 1  lb Brussels sprout
• 2 1⁄2 cups  whole milk
• 3  tablespoons butter
• 1  cup onion, diced small (about 1 small onion)
• 2  garlic cloves, sliced
• 2  tablespoons all-purpose flour
• 4  ounces Canadian bacon, roughly chopped
• 6  ounces  beemster cheese (about 1 1/2 cups) or 6  ounces  aged gouda cheese, grated and divided (about 1 1/2 cups)
• 4  ounces  regular gouda cheese (about 1 cup) or 4  ounces fontina (about 1 cup) or 4  ounces havarti cheese, grated (about 1 cup)
•  freshly grated nutmeg
•  coarse salt
•  fresh ground black pepper

Directions

1. Preheat the oven to 375°F Trim the stem end of each sprout and cut in half.
2. In a medium saucepan over medium-high heat, bring milk to a simmer. Add the sprouts to the milk and simmer for 10 minutes, until they are tender.
3. Meanwhile, melt 2 tablespoons of the butter in a large sauté pan over medium heat. Add the onions and sweat them for 2 to 3 minutes. Add the garlic and sauté until fragrant, about 30 seconds.
4. Stir in the last tablespoon of butter. Once it melts into the onions and garlic, sprinkle the flour in and whisk well to eliminate lumps.
5. Strain the sprouts from the hot milk and set them aside. Slowly whisk the hot milk into the ingredients in the sauté pan. Continue whisking until all the milk is incorporated, lump-free. Stir in the Canadian bacon, all but 1/2 cup of the Beemster, and the Gouda. When the cheese has melted into the sauce, add the Brussels sprouts. Season the sauce with nutmeg, salt and pepper to taste.
6. Pour the mixture into a baking dish or divide between medium ramekins (about 6 ounces). Sprinkle the reserved cheese across the top. Transfer the gratin to the oven and bake for 15 minutes. Broil for 5 minutes to brown the top before serving.