Cut the cauliflower down through the core into steaks about ¾ inch thick. You will get 2 to 3 clean steaks; roast the loose florets right alongside so nothing goes to waste.
Salt the steaks, put them in a bowl with a splash of water (or wrap in a damp paper towel), cover, and microwave about 5 minutes until a knife slides through the stalk with no resistance.
Let the steaks cool and pat the faces dry.
Mix the breadcrumbs, parmesan, garlic powder, and a pinch of salt on a plate. Brush each face with a thin layer of mayo, then press it firmly into the breadcrumbs-parmesan mix so it packs on.
Heat about ¼ inch of neutral oil in a skillet over medium-high. Lay the steaks crust-side down and do not move them until the crust is deep golden and set, about 2 minutes, then flip and crisp the other side.
Warm the cream gently over low heat, do not boil. Off the heat, whisk in the miso, honey, and garlic until smooth. Add the lemon last, off the heat, and thin with a splash of warm water to a pourable sauce.
Pool the sauce on the plate or in a little cup and set the crispy steaks alongside. Finish with sesame, sliced scallion, or a little flaky salt if you like.
