Nan's Shepherd's Pie
Right after you put the potatoes on to cook, begin the filling: Cook the ground beef in a 12-inch skillet over medium-high heat, breaking up the meat with a wooden spoon and turning frequently until the meat is nicely browned, about 7 minutes. Transfer the beef to a plate. Preheat the oven to 500°.
Add 2 tablespoons of the oil to the same skillet. Add the onions and garlic and cook over medium heat, stirring often, until golden and tender, about 6 minutes. Return the browned meat to the pan and stir in the tomato puree and cayenne. Bring to a simmer and cook, stirring occasionally, until the mixture is thickened, about 10 minutes. Stir in the peas and cover to keep warm.
Drain the cooked potatoes well and return them to the pot. Mash well with a potato masher, and stir in the half-and-half and salt and pepper to taste. Spoon the warm meat mixture into a 2 1/2- to 3-quart baking dish and sprinkle the cheddar on top. Spoon the potatoes on top of the cheese, spreading them over the meat, leaving a scant 1-inch border around the edge.
Drizzle the remaining tablespoon of olive oil over the top and bake until the potatoes are golden, about 10 minutes. Let cool for 5 minutes before serving.