First prepare the spinach. Sauté the garlic in the butter for 3-4 minutes and then add the baby spinach and cook for another minute. Strain well and keep warm until service.
Next make the horseradish foam. Put the water, milk, and grated horseradish in a pot and bring to the boil. Season well and blitz with a hand blender, until a foam forms on top. Set aside and keep warm.
To make the coffee rub, mix the thyme, paprika, garlic powder, coffee and chilli together in a bowl. Season each steak with salt and black pepper and seal on a hot pan on both sides for about one minute. Remove from the heat and leave to cool a little.
Rub the meat all over with the coffee mixture and return to the pan and cook the steaks to your liking. Cook for one minute on each side for medium rare (turning three times during the cooking) and for well-done steaks cook them for another two minutes on each side
To serve, place the spinach in the centre, place the beef on top and drizzle with a little port jus. Garnish with the horseradish foam and some fresh rosemary.