Saute onion in 1 T fat until soft and translucent, about 4 minutes. Raise heat medium high and add livers, browning them quickly while stirring occasionally. Season with some salt and pepper.
While livers are still slightly pink on the inside, remove all contents of pan to food processor. Puree. Add the remaining 2 T fat, crackers, seasonings and eggs. Process until smooth. Should be firm and smooth, not stiff or dry. Add a little more fat if necessary.
Taste and adjust seasonings. Seal tightly and refrigerate at least 4 hours before serving.