Prepare by bringing a large pot of salted water to a boil. Add cauliflower florets and blanch for 4 to 5 minutes until tender but firm. Drain and cool.

Melt butter in a medium saucepan over medium heat. Add minced garlic and sauté until fragrant. Pour in heavy cream and let simmer. Whisk in Gruyere until smooth, then season with nutmeg, salt, and pepper.

Preheat your oven to 375°F (190°C). In a greased baking dish, layer the cooled cauliflower. Pour the cheese sauce over it.

In a bowl, combine panko, Parmesan, thyme, and melted butter. Mix and sprinkle over the cauliflower.

Bake for 20 to 25 minutes until golden and bubbly. Broil for 1 to 2 minutes for extra crispiness.