Be sure to cut the lemons as thinly as you possibly can. Paper thin. (You can see in the photo above how thin we're talking.) I actually started using a mandoline, but couldn't get the slices thin enough. I ended up using a sharp knife, which worked perfectly.  Thin slices will ensure that the rinds get nice and soft as the lemons roast and you won't get a huge mouth full of tart, bitter flavor. Next time, I think I'll also cut the lemons into half moons instead of circles just to make the pizza a little easier to eat. You also want to be sure to use part skim ricotta here. Full fat is too greasy and  will leave puddle of oil and a soggy crust.