Preheat the oven to 200˚C (400˚F). Heat olive oil in a non-stick pan over medium low heat; add garlic and fennel. Saute until tender, about 3-4 minutes.
In a pot of boiliing water, cook the cauliflower until tender. Add to the fennel and garlic mixture. Cook an additional 4-5 minutes. Remove from heat; add cream and 1/2 cup of cheese and toss together. Season with thyme and salt and pepper where needed.
Pour into a lightly sprayed baking dish. Stir breadcrumbs and parsley together and sprinkle over cauliflower mixture. Top with remaining cheese.