Tunisian Penne with liver

INGREDIENTS (for 4 persons):350g of Penne,2 onions,2 spoons of oil,40g of butter,200g of liver of lamb,salt , pepper,1dl of vinegar,2dl of bubble of meat,100g of mushrooms,1 spoon of chopped parsley.

PREPARATION:Return the chopped onion in the mixture oil-butter with the liver cuted in pieces. Frit them a few moments. It is necessary to keep them rosy. Degrease them thaw with the vinegar , cook them until the liquid reduces on the half. Add the bubble of meat, the mushrooms cook until boiling. Add the cooked pastes then leave them on a soft fire until evaporation of the liquid. Poached on each plate and strew with chopped parsley.