Preheat oven to 350 degrees.

Line two baking sheets with parchment paper.

Combine all ingredients in a mixing bowl; stir until powdered sugar is completely absorbed into the peanut butter mixture.

Using a Tablespoon measuring spoon, gently roll mixture into small balls and place on the baking sheets.

Lightly press the balls with a fork to gently flatten.

Bake cookies for 8 - 10 minutes until just lightly brown on the edges; be careful not to overbake or cookies will harden.

Remove from oven and cool for 5 minutes, then sprinkle additional powdered sugar over tops, if desired.