Sichuan Steak au Poivre with Scallion Mashed Potatoes

Name: Sichuan Steak au Poivre with Scallion Mashed Potatoes
Ingredients: 1 1/2 pounds Yukon gold potatoes, about 5 potatoes; 2 large cloves garlic; Salt; 1 cup half-n-half or whole milk; 3 tablespoons butter; 1 bunch scallions, 5 to 6; White pepper; About 2 teaspoons Sichuan peppercorns; 1 tablespoon black peppercorns; 4 steaks (6 to 7 ounces) beef tenderloin filet, each about 1 1/4 inches thick; Kosher salt; 2 shallots; 1 inch ginger root; 2 cloves garlic; EVOO; About 1/4 cup Shaoxing Chinese sherry or 2 tablespoons cognac or brandy; 1 cup beef bone broth or stock; 1/4 to 1/3 cup creme fraiche; Upland cress or watercress, to serve