In a 12 to 14inch saute pan, heat oil until smoking. Dredge
the chicken livers into the seasoned flour and shake excess flour off. Saute chicken
livers until crisp
and golden brown, about 8 to 10 minutes, and remove to plate. Add leeks
to pan and cook until leeks are softened, about 8 to 10 minutes. Add chicken livers back to pan, add vinegar and butter and cook until liquid is reduced by half. Add endive to pan. Toss to coat and serve immediately.