Yellow (Yukon gold) potatoes -- 2 pounds
Oil -- 1/2 cup
Lime or lemon juice -- 1/4 cup
Ají amarillo chile paste (optional) -- 2 or 3 tablespoons
Salt and pepper -- to taste
Filling (see variations) -- 2 cups
Hard-boiled eggs, sliced into rounds -- 2 or 3
Pitted black olives -- 6 to 8( optional)
Place the potatoes in a large pot of cold, salted water. Bring to a boil and cook the potatoes until they are tender and cooked through. Drain and set aside to cool.
When the potatoes are cool enough to handle, peel them. Put the potatoes through a ricer or mash with a potato masher until smooth. Stir in the oil, pepper paste if using, lime or lemon juice, salt and pepper to taste.
Line a casserole dish or baking pan with plastic wrap, pressing it down to fit the dish. Spread half the potatoes into the bottom of the dish and smooth out. Spread the desired filling evenly over the potatoes. Spread the remaining potatoes evenly over the filling. Press down gently to firm up your causa. Cover and chill thoroughly.
Lay a serving platter upside-down over the top of the causa dish. Using both hands, flip the dish and platter over, letting the causa fall onto the platter. Remove and discard the plastic wrap.
Garnish the causa decoratively with the hard-boiled eggs and olives and, if you like, a sauce. Cut into portions and serve.
CAUSA RELLENA VARIATIONS
Peru has hundreds of varieties of potatoes. Bright yellow types are usually used for causa rellena, their color boosted by the ají peppers. Yukon gold are a good substitute in the United States. Fillings: Chicken or seafood salads bound together with mayonnaise are very common causa fillings. Miriana, uses cooked salmon-lightly broiled in the oven, or even grilled salmon.
Vegetarian fillings include sliced avocados, sliced or grated cheese, sliced or chopped tomatoes, corn kernels, thinly sliced red onions.
Causa takes its name from the old Incan Quechua word kausaq, which means "giver of life," another name for the potato. Rellena is the Spanish word for "stuffed" or "filled."