Remove tubes and excess fat.
Season and color quickly on all sides in hot fat to seal the pores.
Place into a small braising pan or any pan with a tight fitting lid which may be placed in the oven or in a casserole.
Place the hearts on a lightly fried, sliced vegetables.
Add the stock , which should be two-thirds of the way up the meat , season lightly.
Add the bouquet garni and paste and if available add a few mushroom trimmings.
Bring to the boil, skim and cover with a lid and cook in a moderate oven 150-200 degrees Celcius.
After approx. 90 min cooking add the espagnole, reboil, skim and drain.
Continue cooking till tender.
Remove hearts and correct the seasoning, color and consistency of the sauce.
Pass the sauce on to the sliced hearts in an entree dish.