Grab a 2 quart casserole dish and preheat the oven to 350 degrees.
If you are using fresh Brussels Sprouts, this is the time to boil them as directed in the notes below. Also, if you are frying bacon, this is the time do that.
In a large skillet, over medium-high heat melt 2 tablespoons coconut oil (or use butter) and saute 1 cup onion for about three minutes or until softened, add 2 cloves of minced garlic, and cook one more minute.
Add two tablespoons flour and whisk into onion/garlic. Let cook one minute before adding the 1 cup of half and half, 1/4 teaspoon dried thyme, and 1/4 teaspoon pepper. Bring to a boil and whisk constantly until thickened.
Add in the 1/3 cup grated Parmesan and mix until melted.
Add in the drained Brussels Sprouts and toss to combine. Pour into your baking dish and bake for 30 minutes or until bubble and the Brussels Sprouts are tender and cooked.
Remove pan from oven and top with 1/2 cup sharp cheddar cheese and bacon pieces. Return to oven for about 8 more minutes, or until the cheese is melted.