Preheat oven to 450°F.
Toss the cauliflower with 3 tablespoons of the olive oil. Season with salt and pepper and spread out on a sheet pan or shallow casserole dish. Place in the center of the oven and roast for 10-12 minutes stirring once or twice until cauliflower is tender and starting to brown in spots.
While the cauliflower is roasting, toast the breadcrumbs in a small skillet. Heat the remaining 2 tablespoons of olive oil in the skillet, add the breadcrumbs and toss until brown and crispy. Remove from the heat and place in a small bowl. Combine the garlic, parsley and lemon zest and mix to combine.
To finish, remove the cauliflower from the oven, toss with the crabmeat and garlic, parsley mixture. Return to oven and roast for 4-5 minutes more. Squeeze lemon juice over top and sprinkle with the toasted breadcrumbs.
- It is preferable to use homemade breadcrumbs from stale country style bread for this dish. The toasted breadcrumbs provide a crunchy contrast to the cauliflower that is not achievable with the finely ground breadcrumbs available in the grocery store. When sufficiently dry, pulse stale country style bread that has been cut up in the work bowl of a food processor until coarsely ground.