Step 1Heat the oven to 325 degrees.
Step 2Clean the livers: Use a small knife to remove the connective veins from the chicken livers and discard the veins. Line a large plate with paper towels. Place the chicken livers on the paper towels and pat them with a wad of paper towels to get out the excess moisture. Season the livers very generously with salt and pepper, gently massaging in the seasoning with your hands.
Step 3In a large saute pan heated over high heat until it is almost smoking, add one-fourth cup olive oil. One by one, add the chicken livers. Adding one at a time prevents the pan from cooling too much, and it ensures you will have room for all of the livers because they shrink immediately when they hit the pan, allowing more to fit. Cook the livers until they're a deep brown, about 2 minutes on each side.
Step 4Add the pancetta to the pan with the livers, reduce the heat to low, and continue to cook until the pancetta fat is rendered, 1 to 2 minutes. Stir in the garlic and cook until aromatic, about 1 minute.
Step 5Stir in the brandy, shaking the pan to deglaze, and cook the brandy for about 30 seconds. Remove the pan from heat.
Step 6Dump the contents of the pan onto a large cutting board, making sure to get all the flavorful bits from the bottom of the pan. Pile the parsley, shallots, capers and lemon zest on top of the chicken livers and drizzle over it the lemon juice and one-fourth cup oil.
Step 7Chop everything together coarsely with a large knife. Drizzle over another one-fourth cup olive oil and continue to chop, regathering the ingredients into a mound from time to time. Continue to chop until the livers are the consistency of coarse paste, almost pureed but with more texture. Add additional olive oil as needed; the livers should be moist and glistening but not so loose the pate won't stand up.
Step 8Serve immediately, or cover and refrigerate before using. The pate can be made up to a couple of days in advance; bring to room temperature before serving. This makes about 2 cups pate.