Melt 1/2 of butter in a skillet. Add onion, garlic and chicken livers and cook gently 5 minutes, stirring constantly.
Stir in curry powder and cook 1 minute. Add chicken stock and cook gently 5 minutes, stirring and turning livers frequently. In a blender or food processor, process chicken liver mixture and hard-boiled eggs to a smooth puree.
Add salt, pepper and cayenne pepper. Turn mixture into a serving dish or terrine. Smooth surface. Melt remaining butter in a saucepan and pour over surface of pate. Let set slightly, then garnish with bay leaves and lemon pieces, if desired. Chill several hours or overnight before serving with bread.
VARIATION: Add curry powder to taste to melted butter topping.