Mix margarine, sugars, peanut butter, eggs, and vanilla together until well combined.

Then add soda, salt, and flour. Mix just until combined. This is a really soft dough. This is where you can add chocolate chips or roll the cookies in sugar, if you like.

Bake at 350 degrees for 10-12 minutes, just until they start to get a little brown (you'll probably think they need to cook longer but don't do it unless you want crunchy cookies). Then cool on the cookie sheet for a few minutes before putting them on a cooling rack. Makes around 4 dozen cookies.