This is, by far, the best way to eat your steak au poivre. A big plate of rosemary salted roast potatoes, piled high with cubes of medium rare peppercorn steak, and bathed in a rich peppercorn sauce. And of course there're crispy onions on top!
Method
Start by peeling and cutting the potatoes into pieces just bigger than bitesized. Cook them in a pot of cold water, with peppercorns and rosemary, and a good pinch of salt, until folk tender. Allow them to cool on a rack completely. Once cool, cover with the plain flour and toss them about to ruffle the edges. Preheat some vegetable oil in a small sauce pan. Place the potatoes on a baking tray with garlic and rosemary. Carefully pour the hot oil over the potatoes, before roasting in the oven at 180°c for 45 minutes, flipping halfway through. Fry the finely sliced shallots in a small saucepan of vegetable oil over medium low heat, until golden. They'll feel 'soggy' at first, but as they cook, they'll crisp up! Prepare the steak by allowing it to sit at room temperature for 30 minutes. Dab with a paper towel to remove moister from the surface, before heavily salting both sides, and seasoning one with corse peppercorns. Cook in a heavy skillet over medium heat, with a couple tablespoons of oil. Sear the first side hard, maintaining a controlled, but high temperature. After 5 and a half minutes, flip, and sear for another 2 minutes. Then lower the heat, add the butter, garlic and thyme and begin to baste and cooking for another 3 minutes.Remove the steak from the skillet, and pour over the leftover butter and aromatics. The steak should at 55°c, and will rise to 60°c for a medium steak. Or give the steak a poke, if it's soft like how pressing a finger on the palm of your hand, it's time to rest! In the same pan, add another tablespoon of butter if needed, and keep over medium heat. Add the chopped shallots and garlic, cooking until fragrant, before adding thyme, and deglazing with the alcohol. Once the smell of the alcohol has gone, add the beef stock, cooking off half, before adding the cream, and cooking off half again. Add the green peppercorns and mix through. Pile the roast potatoes high on a platter, followed by the steak, sliced into cubes and the peppercorn sauce. Finish with the crispy shallots and chives. 
