Cream butter using a mixer. Grate the lemon zest and squeeze out the juice. Mix into the butter and season well. Pour into a piping bag, pipe rosettes on baking paper and leave to cool.
Peel the bottom third of the asparagus and cut away the woody end. Bring sufficient water to the boil in a wide pan. Halve the lemon and add it with the butter, salt the water. Add the asparagus and cook until just below boiling point (approx 15-20 minutes).
Season the steaks and sear well on both sides in the hot butter for 1 minute each side, remove and place on a preheated plate. Cook in a preheated oven at 80 degrees for about 25 minutes. In the last 2 minutes, increase the temperature to 200 degrees, so that the meat is well heated.
Arrange the asparagus and steaks in portions on plates and add some lemon butter on the meat. Sprinkle the asparagus with some freshly ground pepper and serve immediately.
Goes well with potato gratin or boiled potatoes.
Source image and recipe: Kathrins Natura-Beef Fleischküche. Available in german in the webshop of Suckler Cow Switzerland.