Preparation:

Pour 2 litres of milk and 1 teaspoon of salt into a saucepan.
Stir continuously and, when it reaches 80º, turn off the heat and add 8 tablespoons of vinegar; stir and watch as the curds separate from the whey.
Leave to stand for a few minutes whilst placing 2 strainers over 2 bowls and covering them with 2 squares of cotton cloth.
Divide the cheese between the 2 strainers. Once they have drained thoroughly, stir in the butter and chill for 1 hour before serving.