Peel, wash and chop the potatoes and carrots. Cook in boiling salted water for about 20 minutes. Drain potatoes and carrots. Warm up milk and butter. Add to the potatoes and carrots and mash coarsely. Season to taste with salt and pepper. Heat oil in a pan.
Dab butterfly steaks dry and fry them in the pan for 2-3 minutes on each side, remove. Deglaze the frying stock with broth. Stir in sauce thickener, bring to the boil. Season to taste with salt and pepper. Rinse cress and cut from the bed. Sprinkle over the puree. Arrange puree, butterfly steaks and sauce on plates