Remove the beef steak from the refrigerator half an hour before cooking so the meat can come to room temperature. Pat the steak dry all over just before cooking.
Boil or steam the cauliflower florets for ten to twelve minutes until very tender. Meanwhile, place a frying pan over high heat and let some ghee become very hot. Cook the steak for approximately two to three minutes per side for a medium-rare result. During the last minute, add the fresh thyme to the pan so its aroma infuses into the cooking fat.
Remove the meat from the pan, wrap it in aluminum foil, and let it rest for at least five minutes. Drain the cooked cauliflower and let the florets steam briefly in the pan. Add the grass-fed butter, a pinch of freshly grated nutmeg, and some Celtic sea salt. Use an immersion blender or potato masher to process everything into a smooth, creamy puree.
Slice the rested beef steak. Divide the warm cauliflower puree onto plates and place the sliced meat alongside. Finish the dish by grinding coarsely ground black pepper over the steak and serve immediately.