Thoroughly rinse the tripe and cow's trotter, and rub vigorously between both hands. Drain and cut into pieces.

Cook the tripe and the cow's trotter in a large volume of boiling salted water for 1h30 by changing 3 times the cooking water (the water must always be boiling).

Reserve the last cooking water and drain the tripe and cow's trotter.

In a cast iron pot or Dutch oven, pour the olive oil and heat it over medium heat. Fry the tripe and cow's trotter in this oil for 5 minutes, stirring regularly.

Add garlic, paprika, tomato paste, salt, pepper, harissa and half of the cumin. Stir well.

Pour the reserved cooking liquid at a height of 1 inch (3 cm) above the tripe. Reserve the rest of the cooking juices.

Cover and cook for 30 minutes over low/medium heat.

Then reduce the heat and cook covered and over very low heat for 4 hours.

During cooking, if the sauce is lacking in the pot, add some of the reserved (boiling) cooking water in small amounts each time.

If there is no sauce and no more cooking juices, add boiling water, always in small amounts.

Ten minutes before the end of cooking, add the other half of the cumin.

Serve very hot by placing a few pieces of mixed tripe in a dish on a generous bed of sauce.