In a large mixing bowl, combine old-fashioned rolled oats, natural peanut butter, maple syrup or honey, and melted coconut oil. Add lemon zest, fresh lemon juice, vanilla extract, and salt. Mix until sticky dough forms.

Taking small amounts of the mixture, form them into round cookies about 2 inches in diameter. Place on a parchment-lined tray.

Cover the tray with plastic wrap and refrigerate for approximately 30 minutes until firm.

After chilling, serve the cookies cold. Store leftovers in an airtight container in the fridge for up to a week.