jQuery change css attribute slowly

I have this code

$('#uiAdminPanelMenu li a').hover( function(){
    $(this).css('background-color', '#D3E1FA';
 },
 function(){
    $(this).css('background-color', '#F4F4F4');
});

it changes the background color of the link, but I want it to change it slowly, kinda like fade effect, but for this case.