Lamb Stew W/ Chestnuts & Pomegranates

• 2 onions
• 1 1/2 lamb (boneless)
• 1 garlic clove fine (minced)
• 270 gr chestnuts (roasted)
• 240 ml pomegranate juice (fresh)
• 350 ml chicken stock
• 120 gr walnuts fine (minced)
• 60 ml sunflower oil
• 45 ml lemon juice squeezed (freshly)
• 34 gr tomato paste