Demi-Glace sauce

5 kg of veal (but you can fınd beef also ) bones cartilage and marrow parts 5 carrots 5 cellary stıcks 4 onions tomato paste and a lot of gas to cook them for mın of 18-24 hour 10 lıters of water 2-3 spoon full of veg oil ... cook all ıngrıdıents ın oven for about an hour or until they get brown (45min for veg and 1-15 h for bones at 220) then place ın cold water (about 10-12 lıters) and sımmer for 18 hours after sımmerıng take all solıd parts wıth an aıd of wıre mash and boıl agressıvly untıl you have a consıstancy of lıght lıght cream never season or salt untıl you are ready...... enjoy you can save them for a year in fridge (frozen ) when its time to use the cubes season themm as you wish before use