Preheat the oven to 350°F (175°C)
Line a baking sheet with parchment paper
In a bowl, mix 1 cup peanut butter, 1 cup sugar, and 1 egg until smooth
Add 1 teaspoon vanilla extract if desired
Stir in 1/2 teaspoon baking soda and a pinch of salt if desired
Scoop tablespoon-sized portions of dough onto the baking sheet
Flatten each cookie with a fork in a crisscross pattern
Bake for 8 to 10 minutes until lightly golden
Let the cookies cool on the baking sheet for 5 minutes
Transfer the cookies to a wire rack to cool completely