Place the liver pate in a bowl. Add vinegar, breadcrumbs, sugar, salt and freshly-ground black pepper. Pour 40 milliliters of cold water into the bowl and stir.
Finely chop the garlic and onions. Heat the lard in a large pan and sauté half the garlic until golden and crispy. Remove and set aside.
Add the onions and the remaining garlic to the pan and sauté until soft and translucent. Pour the pate mixture, including the liquid, and bring to a boil. Let it boil rapidly for one minute.