Matzo Sandwiches with Chopped Liver Onions and Egg

Name: Matzo Sandwiches with Chopped Liver, Onions, and Egg
Ingredients: 1 large yellow onion; 1 medium shallot; 2 cloves garlic; 1 pound chicken livers; 1 teaspoon kosher salt, plus more as needed; 1/2 teaspoon freshly ground black pepper, plus more as needed; 1 to 2 tablespoons schmaltz or olive oil, divided; 1/4 cup kosher for Passover white wine (something like this is great); 2 large hard-boiled eggs; 1/2 medium red onion; 1/2 bunch fresh parsley; 6 large hard-boiled eggs; 3/4 cup prepared horseradish; 6 to 12 sheets matzo