Preheat oven to 350 degrees and grease cookie sheets.
Beat together peanut butter and sugar in a large bowl until smooth. Add egg, baking soda, vanilla, and cinnamon. Mix until all ingredients combined.
Pinch off approximately 1 teaspoon of batter, roll into a ball, and place on cookie sheet. Complete this step until all batter is used, placing cookies about 1 inch apart.
Pour a little bit of cold water into a dish. Take a fork and dip into the water and then slightly mash the cookies to create a cross-hatch pattern.
Bake until puffed and a golden pale, about 10 minutes. Let cool on baking sheet for 2 minutes, then transfer to serving plate to continue cooling. Cookies can be stores in an air-tight container at room temperature for up to 5 days.