This is a recipe I learned three days ago from my paternal grandmother. She learned it from a friend who works with underprivileged children and families who cannot always afford the junk foods enjoyed by the upper third of the U.S. population. This recipe features easily obtainable and inexpensive ingredients, and more importantly, it only requires four ingredients, and the only point in the recipe that requires adult supervision is the removal of the cookie tray from the oven.
Peanut butter (1 cup)
Sugar (1 cup)
Vanilla (1 teaspoon)
Something to stir the ingredients
Cookie sheet or other flat pan
Preheat oven to 250 Fahrenheit, or as close to it as possible.
Mix all four ingredients in a bowl.
Spoon out the mixture in 1-2" blobs on the cookie sheet. You should have enough for about 12 cookies.
Place cookie sheet in the oven for ten minutes or until the cookies flatten out and look a little bit crispy around the edges. You don't want them changing colour very much, because a darker brown means they're more burnt than baked.
Remove the cookie sheet and place it on a surface that is heat-resistant. When the cookies are cool enough to handle, carefully remove them from the sheet.
Clean up your supplies. By the time you're done, the cookies will be cool and solid enough to pick them up and eat them. Expect them to be a little bit crunchy; they go very well with milk.
Note: Crunchy peanut butter adds to the texture of the cookies but increases the chance that you'll burn them more than you want. For this recipe, personal experience advises creamy peanut butter.
Belated Note: The reason I learned this recipe in the first place is my paternal relatives' tendency to severe allergies. My first cousin has Celiac Disease (that is, she cannot metabolize wheat glutins), and my father and grandfather are both violently allergic to all dairy products. My grandmother does the cooking at virtually all our family gatherings, so she keeps a Rolodex full of wheatless and non-dairy recipes.
As for store-bought (or store-filched) peanut butter cookies... the vast majority of them contain wheat and/or dairy in quantities sufficient to produce anaphylaxis in my family members.