4 Idaho potatoes, peeled and chopped
Salt and freshly ground pepper
2 tablespoons extra virgin olive oil (EVOO)
4 flat-iron steaks (6 ounces each), (each about 1-inch thick)
2 tablespoons butter
3 shallots, finely chopped
2 tablespoons all-purpose flour
2 tablespoons sherry or white wine
1 cup plus 2 tablespoons chicken stock, divided
1 cup plus 2 tablespoons milk or cream (whichever you prefer), divided
1 1/2 cups shredded Swiss cheese
1 box frozen peas (10 ounces)
2 tablespoons Dijon mustard
1/2 cup flat leaf parsley (about a handful), chopped
Place the potatoes in a medium saucepot with some salt and cover with cold water. Place the pot over medium-high heat and bring the liquid to a bubble. Reduce the heat to medium and simmer potatoes until tender, 12-15 minutes. When the potatoes are working, place a large, cast-iron skillet over medium heat with 2 turns of the pan EVOO, about 2 tablespoons. Season the steaks with salt and pepper, and cook them in the pan until caramelized and cooked to your desired doneness, 8-10 minutes for medium. Let the steaks rest a couple of minutes before slicing them. While the meat and potatoes are working, place a medium skillet over medium-high heat with the butter. Cook the shallots in the melted butter until softened, 5-6 minutes. Season with salt and pepper, and sprinkle the flour over the butter. Cook for another minute then add the sherry to the pan. Cook the sherry for a minute then whisk in 1 cup each of the chicken stock and milk. Bring the liquids up to a bubble and simmer until the gravy has thickened, about 1 minute. Turn the heat under the pan down very low and gently stir in the shredded cheese until melted. When the potatoes have finished cooking, drain them, add the peas to the bottom of the pot they were cooked in and then toss the potatoes on top of the peas to heat them up. Add the remaining 2 tablespoons each of chicken stock and milk, the Dijon mustard and parsley to the pan and mash up the potatoes. Season with salt and ground pepper to taste.
Serve the sliced steak with a heaping ladle of fondue gravy over the top and a scoop of the potatoes alongside.