Simple Cookies (Gluten-free)

My friend gave me this recipe--I think she invented it but I'm not certain. In any case, as she pointed out, it's just intended to be a simple cookie recipe, but it also happens to be gluten-free. And dairy free. Cool!
1 cup peanut butter
1 cup sugar
1 egg

Mix together. Roll into balls and put on a greased cookie sheet. Dip the bottom of a cup in sugar and then press down on the top of each ball to flatten it a bit (I use a tupperware cup, thus the double circle in each cookie ☺)
Bake at 350 for about 10 minutes.

You can also add in all sorts of other things, nuts, chocolate chips, oatmeal...whatever you like. You may need to bake them as bar cookies or change the cook time if you do those things.

Here is one rendition I've done:
Egg, peanut butter, sugar
1/2 cup rolled oats (which i ground in the food processor so it was more like flour than oatmeal) 1/2 cup applesauce
about 1/3-1/2 c chocolate chips.
I put it in a 9x9 pan and baked it at 350 for 25min. It could have gone a little longer probably--it was really mushy when it was hot (I ate it out of a bowl rather than as a bar)