Position an oven rack in the center of your oven and then preheat the oven to 350F degrees. Line 2 baking sheets with parchment paper or silicone liners.
In a large bowl, beat the peanut butter, brown sugar, egg, and baking soda together with an electric mixer on medium, until well blended.
Drop level teaspoons of dough onto the prepared baking sheets, spacing them about 1-½ inches apart. (This is a small amount since you want enough for 60 cookies.)
Bake until the cookies are puffed and starting to lightly brown around the edges, 8 to 10 minutes.
Remove from the oven and let cool on the baking sheets placed on wire cooling racks for 5 minutes. Then transfer the cookies directly to the wire racks to cool completely.
