1. Pre-heat the oven to 375 degrees F and lightly grease roughly 3 quart baking dish.
2. Bring a large pot of water to a boil. Cook the Brussels sprouts until tender, about 6-8 minutes depending on how big the sprouts are. Drain and lightly dry with a towel. Set aside.
3. In a large saucepan over medium heat, add in your butter. Once butter is melted, add in the garlic and sauté for 2 minutes.
4. Whisk in the flour and cook for 1 additional minute. Whisking constantly, slowly add in the milk and continue to cook until the sauce begins to really thicken. This will take about 5-7 minutes.
5. Remove from the heat and mix in 1 1/2 cups of the cheese. Season with salt and pepper.
6. Mix the Brussels sprouts into the cheese mixture. Mix well, then pour into your prepared baking dish. Top with the remaining 1/2 cup of cheese and bake for 25 minutes. Watch the last 10 minutes to make sure the cheese isn’t burning and cover with foil if so.
7. Let cool slightly and enjoy!