In the bowl of a food processor, pulse the bread until it forms into crumbs.
In a large non-stick frying pan, heat the butter over medium heat. Add the bread crumbs and cook, stirring constantly until all the butter has been absorbed and the bread crumbs are toasted, about one or two minutes.
In a medium bowl, whisk together the cream and flour. Add the capers, bacon and 55g of the Gruyere. Season with salt and pepper, to taste.
Bring a medium saucepan of water to a boil over high heat. Add the cauliflower and cook for two minutes. Drain the cauliflower and toss with the cream mixture. Pour the cauliflower mixture into the prepared baking dish. Sprinkle with the bread crumbs and remaining cheese.
Drizzle with olive oil and bake for 35-40 mins until the cheese has melted and the top is golden brown.