To make the puree, set a saucepan over medium heat and add the oil. Add in the onion, ginger, salt, and pepper. Cook, stirring often, until the onions soften, about 5 mins. Add the sweet potatoes and stir over the heat for 1 minute. Pour in the cider and bring to a simmer. Cover, reduce the heat to low, and simmer until the sweet potatoes are tender, about 25 mins.

Transfer the contents of the saucepan to a high-speed blender or food processor and process until smooth, scraping down the bowl at least once.

To make the steaks, heat the oven to 375F with the rack in the middle of the oven. Trim cauliflower heads from laves, then slice the heads in half through the stem. Starting at the cut side of each cauliflower half, make ½-inch-thick slices for as long as the slices will hold together. You should end up with about 4 slices per head.

Set a large cast-iron skillet over medium heat for a few minutes. Swirl in 1 TB of oil, then slip in the cauliflower slices (probably no more than two). Cook, turning once, until browned, even blistered a bit, about 8 minutes in total. Transfer to large, tin foil-covered baking sheet. Continue frying the remaining slices in more batches if necessary (if you don't have any more slices to bake than your pan fits in one go, no need to transfer the slices onto a sheet - just put the whole skillet into the oven).

Once all the cauliflower slices have been fried, brush them with the chili sauce. Bake until tender and bubbling at the edges, about 10 mins.

To serve, divide the sweet potato puree between the plates and top each with a cauliflower steak.