The bottoms always burn

[Manduck]

But with parchment you get the joy of wastefully throwing it away afterwards!

[treis]

@DoctorJ

What color are your pans? Remember that black conducts heat more rapidly than other colors (as anyone who has ever owned a black car can tell you), so non-stick-type pans that are black or dark gray (especially as they get older) conduct heat more readily straight to the bottom of the cookie. I like plain half-sheet pans, which you can get at a restaurant supply store for about six bucks apiece. (I’ve come to think of this sort of bakeware as disposable, so I don’t make much of an investment.)

Greasing the pan too much can also cause burning. One thing to try, if you haven’t, is lining the pan with parchment (available at most grocery stores and any competent gourmet shop).

Do you trust the temperature of your oven? Unless your oven is brand new, and even then, I would invest ten bucks in a decent oven thermometer. Mine (a monstrosity in Harvest Gold, apparently installed when that color was considered attractive) consistently runs 75 degrees hotter than the dial indicates.

Moving the oven rack away from the burners, or putting the cookies on a higher rack, might work. If you have a pizza stone or something in the bottom of the oven, get rid of it (for this purpose). Finally, clean your oven; a dirty oven results in a very unequal distribution of heat.

DoctorJ there should be a fairly easy way to adjust your temperature settings, check your user manual.