Food processor - Quickly pulse liver until crumbly, remove. Pulse garlic cloves until minces. Add onions and pulse until chopped. Add remaining ingredients and process until combined.
Or pre chop/ grind livers, garlic and onions. Mix all ingredients together by hand.
Put in 2 loaf pans. Cover with foil. Set in a pan of water and bake at 350° for 1 hour. Reduce heat to 250° and cook for 2 hours longer.
Cool ½ hour. Leave the foil on top and place brick on top for ½ hour. Drain to remove excess fat. Replace foil and brick; place in refrigerator overnight. Finished pate will be about an inch thick.
Serve chilled. This can be prepared ahead of time, wrap each loaf in foil then put in a zip to lock bag.
Notes
You will need 2 bricks or something of the equivalent size and weight to press the pate down after baking.