Preheat oven to 400°. Remove leaves and trim the end of the cauliflower. Cut into four 1/2" steaks from the center of the cauliflower. Reserve the small florets that break loose, and break into small pieces. Season cauliflower with the salt and pepper (and a dash of paprika and cumin if you'd like). Place seasoned cauliflower onto a baking sheet and drizzle with olive oil, and roast in the oven for about 30 minutes, flipping once, until crispy around the edges.
Quarter the tomatoes and place them onto a rimmed baking sheet with the garlic cloves. Halve the onion (reserve one half) and quarter one half. Break apart and scatter the onions in the baking dish with the tomatoes and garlic. Drizzle everything with olive oil, season with salt and pepper, and roast in the oven for 30 minutes as well, stirring as needed. Once done, remove from oven and transfer to a heated skillet with a bit of olive oil. While sauteeing, mash up the garlic, tomatoes, and onions with a wooden spoon, leaving it chunky. Allow it to reduce a bit, then remove from the heat. Toss in 1 tbsp of the chopped cilantro, and add salt and pepper to taste.
While everything is in the oven, make the relish. Finely dice the remaining half an onion, and place in a bowl with the reserved cauliflower bits, chopped olives, cilantro, champagne vinegar, and Mike's hot honey. Mash everything together until it's incorporated.
To assemble, spread the tomato sauce onto each plate, then place the cauliflower on top. Garnish with olive salsa, and serve while still warm.