Preheat the oven to 375°F. Line a 9-by-5-inch Pyrex loaf pan with foil and brush the foil with oil.

In a small skillet, heat the oil over low heat. Add the onion and garlic and sauté until lightly golden, about 5 minutes. Remove from the heat and let cool.

Transfer the onion mixture to a food processor and add the potato and egg. Pulse until very smooth.

Transfer the mixture to a medium bowl, and add the ground meat, tomato paste, ketchup, soy sauce, parsley, and salt and pepper to taste. Mix with your hands until thoroughly combined. Place the meat in the foil-lined pan and smooth the top.

Place in the oven and bake for 55 minutes, or until lightly browned on top. Remove from the oven and let rest for 30 minutes before slicing (it will fall apart if it’s too hot.)