Fry finely diced onion (1 onion) and finely diced garlic (as many cloves as you like! I usually use 2 large ones) in a combination of butter and olive oil.
When softened, add the chicken livers and fry until cooked through (this generally takes only 5 minutes or so - and they're better under rather than overcooked).
Season with salt, pepper, and whatever spices you like or have to hand. I think the original recipe I used called for mace.
Tip everything into a blender.
Into the frying pan add a small dollop of tomato puree (probably a dessert spoon max) and a generous sloosh (technical term) of brandy and stir this together to get all the last bits from the pan. Add to the blender.
Add some cream - not too much, perhaps 4 tablespoons - and then blend the whole thing till smooth.
Pour into your dish and let it firm up.
I make this fairly regularly and it's lovely. It's also a fairly robust recipe, so you can fiddle around with it in terms of seasoning.