1. Bring the meat to room temperature by removing from the fridge half an hour before cooking.
2. To make the potato cake, peel and grate the potatoes, then sprinkle with salt and place in a clean tea towel. Roll the tea towel up lengthways and twist its ends in opposite directions over a sink, getting rid of as much moisture as possible – there will be quite a bit. Unroll the tea towel and place the grated potato in a small bowl and add thyme leaves, mixing well.
3. Melt half the butter with the olive oil in a heavy-based 15–18 cm wide non-stick frying pan. Add the potatoes and push the mixture down with a potato masher or the back of a spoon. Cook over low–medium heat for about 4–5 minutes until it becomes crispy round the edge and the bottom of the potatoes turns brown. Carefully turn the potato cake out onto a plate the same size as the frying pan. Melt the remaining butter and slide the potato cake back into the pan, uncooked side down. Cook for about 3–4 minutes until well browned and crisp and slide out onto a chopping board.
4. While the potato is cooking, make the horseradish cream by mixing all the ingredients together in a small bowl. Set aside until ready to serve.
5. Also while the potatoes are cooking, brush the steaks with a little oil and season well with salt and pepper, then cook on a preheated chargrill or ﬂ at grillplate over high heat until done to your liking, turning once. Rest steaks, loosely covered, for 5 minutes before serving.
6. Serve the steaks with a dollop of the cream and a wedge of potato cake.