Plce chicken livers on a few sheets of paper towels to dry (they may stick) and cut off any fat or connective tissue. Season with salt and pepper
Heat a medium sized skillet over medium heat and drizzle with ¼ cup of olive oil. 1 finely chopped shallot and saute until caramelized and soft, about 2-3 minutes. Add garlic and saute for another minute.
Add chicken livers and increase heat if needed to give them a good sear. Sear on first side for 1-2 minutes, then turn over and sear on the other side for another 1-2 minutes until just cooked through.
Pour in sherry and scrape any bits from the bottom of the skillet and reduce heat to medium.
Add capers and stir everything together. The sauce should have thickened but there should still be some moisture.
Remove from heat and place liver mixture onto a clean cutting board (I like to use a plastic cutting board for proteins) and pile the other finely chopped shallot, parsley, lemon zest and lemon juice and rest of the olive oil and give everything a really good chop.
Taste for seasoning and add more salt if needed. If the mixture is on the drier end, drizzle more olive oil and chop it through the mixture.
Spoon mixture on top of toasted crostini and top with parsley, lemon zest and a good drizzle of olive oil. If you have leftover chopped shallot, the added crunch is a nice touch.