Here’s your math - you get two, decent looking “cauli steaks” from a head of cauliflower plus a lot of extra florets that can be used for another meal. If the actual steak shape is not important to you, you can roast florets from two heads in the same spices, at 425’ for 35 minutes and serve them over the labneh with the relish.

Labneh is just a very thick, strained, whole milk yogurt. So, if you can’t find labneh you can sub for a very thick whole milk Greek yogurt or a store-bought hummus, as suggested.