Preheat the oven to 350°F (175°C)

Fill a large pot with water about half-way and boil the water on the stove at medium heat.

Cut the cauliflower into large florets. Place the cauliflower florets into the boiling water and let them cook for 5 minutes.

Strain the water from the cauliflower florets. Pour the florets back into the pot and set aside.

Add the light cream, garlic, thyme, nutmeg, black pepper, and salt to the flour and butter mixture. Whisk everything together.

Remove the pot from the stove. Add half of the Gruyere cheese and half of the cheddar cheese to the cream mixture and mix everything together using the whisk.

Add the cream mixture to the cauliflower and gently mix using a spoon.

Pour the cauliflower mixture into a small, greased baking dish. Spread the mixture evenly in the dish and top with the remaining Gruyere and cheddar cheese.

Put the butter in a small saucepan and let it melt on the stove at low-medium heat.

Add the breadcrumbs, black pepper, and salt to the butter. Use a spoon to continuously turn the mixture until the breadcrumbs are a light golden brown.

Remove the saucepan from the stove and let the breadcrumb mixture cool before sprinkling on top of the cauliflower mixture.

Put the cauliflower gratin in the oven and bake for 25 minutes or until the breadcrumbs are golden brown and the cauliflower is cooked through.

You can set the oven to broil to toast the breadcrumbs to your desired colour if the breadcrumbs aren't your desired colour after 25 minutes of baking the dish.

Remove the cauliflower gratin from the oven once it's done and let it cool for about 15 minutes. Garnish with a bit of thyme and then serve