|Tripe||2 Pound, rinsed and cut into 1 - to 1 1/2-inch or 2 1/2 to 3 centimeter pieces|
|Olive oil||2⁄3 Cup (10.67 tbs)|
|Potatoes||8 Medium, diced|
|Onions||3 , sliced|
|Tomatoes||5 , peeled, seeded and crushed|
|Cayenne pepper||1 Pinch|
|Grated gruyere cheese||3⁄4 Cup (12 tbs)|
Put the tripe into a pan of salted cold water to cover.
Bring to a boil, skim and simmer the tripe for one hour.
While the tripe is cooking, heat half the olive oil and in it fry the potatoes until golden.
Drain them, reserving the oil.
Fry the onions in the reserved oil until they are brown.
Meantime, warm the rest of the oil in another pan, add the tomatoes and a pinch of cayenne pepper, and cook them over medium heat until their juices have evaporated about 10 minutes.
Add the fried onions to this sauce.
Drain the tripe.
Put the tripe and potatoes in an ovenproof dish, cover them with the tomato-and-onion sauce, sprinkle the top with the grated Gruyere, and bake the mixture in a preheated 400° F. [200° C] oven for 15 minutes, or until the cheese is melted and browned.