Heat ¼ cup of your chosen cooking fat in a large skillet over medium high heat.
Add onion, bay leaf, rosemary, thyme, sage, mace and garlic to the pan. Cook, stirring frequently, until onions are well cooked (about 10 minutes).
Add liver to the pan and cook, stirring frequently, until browned on the outside and still pink in the middle (about 3-4 minutes).
Add sherry to pan and bring to boil (you can increase heat to high if you want). Boil 2-3 minutes, until you can’t smell alcohol in the steam.
Remove from heat. Remove bay leaf, rosemary stem, and thyme stems. Add salt and the remaining cooking fat.
Pour hot liver mixture into a blender or food processor. Pulse until smooth.
Pour into the prepared loaf pan (or serving dish of choice).
Once it’s cool enough to touch, make sure to cover with plastic wrap tightly across the entire surface (plastic wrap should be touching the pâté with no air bubbles) to prevent oxidation (you’ll still get some, which is okay, but doing this helps your pâté stay a nice pink color which tastes better and is better for you).
Refrigerate overnight up to a few days before eating.