Answer:
You CANNOT bake peanut butter cookies with only peanut butter and sugar. You need a lot of other ingredients including flour, salt, eggs, etc. You can make a flourless peanut butter cookie with only peanut butter, white sugar, and an egg.
See related links for a peanut butter cookies recipe that does not use flour.
There are "peanut butter drops" which are made by mixing peanut butter and marshmallows, then melting them in the microwave, dropping them on wax paper and sprinkling them with crushed peanuts...that's the closest I've seen to making peanut butter cookies with just peanut butter and sugar.