In a medium bowl, stir together the peanut butter, sugar, and egg until well combined.
Using a 1 Tbsp. cookie scoop, place about 9 level scoops on each prepared sheet pan. Roll each scoop into a ball and place rolled balls about 2" apart. Place about 2 Tbsp. of flour on a small plate. Dip a fork in the flour and gently push down on a ball of cookie dough; repeat a second time making a crosshatch pattern. Repeat for each ball of dough.
Place both cookie sheets in the oven on 2 separate racks. Cook for 5 minutes. Take sheet pans out and replace, top tray on the bottom, bottom tray on the top. Also, rotate each tray, front to back. This will help the cookies bake evenly. Cook an additional 5 minutes. Edges should be just starting to crisp up and center should look cooked. Add an additional minute or two to bake time if necessary. Don't overbake!
Remove sheet pans to a wire cooling rack. Leave cookies on pans until completely cool. Store in an airtight container.