Preheat your oven to 400.
Bring a medium pot of water to a light boil. Add the cauliflower and cook for ten minutes.
In the meantime, let’s make the sauce. To a wide skillet over medium heat, add the butter. Once it’s melted and starting to foam, add the flour. Whisk this until smooth and darker in color, just a couple of minutes. Add the minced garlic, dried thyme and dijon mustard. Whisk until smooth.
Slowly add the cream and milk until the sauce becomes smooth and thick. Give it a pinch of salt and keep whisking as you add half the grated cheese to the sauce. Whisk until the cheese has melted and the sauce is thick and creamy.
Add the boiled cauliflower to the skillet and stir until coated.
Transfer to a baking dish and sprinkle the remaining cheese over the top. Bake for 30 minutes, or until the cheese is browning and bubbly.
Garnish with parmesan cheese and parsley! Let sit a few minutes to cool, then serve.
Serves 6-8.
