To make the filling, we cut the beef needle meat into medium-sized tacos and do the same with the skinless pork belly. In a saucepan we put two tablespoons of olive oil and we add the meat and the onion in julienne, and we lightly poach them, seasoning to taste. Add the grated tomato and let everything cook for five minutes. Then we add the red wine and the cognac and we let the alcohol evaporate.
Add the broth and let the whole cook for about an hour until the meat is very tender. With a hand mixer we blend without leaving a too fine texture so that the meat threads are noticeable. We reserve in the fridge for 24 hours for the flavors to settle.
We cut the potatoes with a mandolin so that they are thin, about 3 millimeters approximately. The we fry over a very low heat in batches until they become manageable and we can shape them. This way we will get the potatoes to be very creamy inside. Then we will finish making them once they are filled.
We put two dessert tablespoons of our meat filling on each potato and we cover it with another, squeezing the edges so that they are more or less sealed. We pass the potatoes through beaten egg white and fry them in abundant and very hot olive oil until they are golden brown. So they remain very crispy outside.
Once the Olot potatoes are browned, we drain them on absorbent kitchen paper and serve them with a salad, warning diners to be careful about the temperature, since they keep a lot of heat and could burn, if they are eaten too quickly.