Gluten Free Shepherds Pie

Name: Gluten-Free Shepherd’s Pie
Ingredients: ½ cup potato starch (not potato flour); Salt and pepper; Dash of cayenne, or more, to taste; 1-1 ¼ pounds cubed lamb meat (½-1-inch from the leg); 2 tablespoons of vegetable oil, plus more as needed; 1 bottle (16 ounces) gluten-free beer, preferably Redbridge or Bard’s; 1 medium yellow onion, diced fine; 3 carrots, cut into small oblique (see note below); 1 cup fresh button mushrooms, sliced; 1 tablespoon tomato paste; 2-3 bay leaves; 1 tablespoon fresh rosemary, chopped; 1 cup peas; 1 teaspoon fresh thyme (optional); 2 pounds potatoes, peeled and cut into 1-inch cubes; ½ stick butter; Salt and white pepper, to taste; ½ cup heated milk (more or less for desired creaminess); Parsley, chopped, for garnish (optional)