Preheat oven to 350°F (177°C). Line a large cookie sheet with parchment paper.
Add quick oats to a small food processor. Pulse a few seconds (about 5 seconds) or just until the oats are about half the size as they were. I don't recommend using a blender because it will blend the oats into flour too quickly. Transfer the oats to a large mixing bowl.
Drizzle melted coconut oil evenly across. Using a spatula, stir the mixture briskly for about 20-30 seconds, stopping a few times to scrape the sides of your bowl, until all of the oats look slightly moistened with coconut oil.
Add in the lemon juice and zest. Stir until evenly mixed in. Add in the maple syrup. Mix with your spatula until the oats are evenly coated in syrup and the mixture start to get clumpy. Taste, and if needed, you can add one more tablespoon syrup or more lemon zest. Avoid adding more lemon juice because that can soften the oats too much.
Using a 1-tablespoon cookie scoop, pack 1 tablespoon of oat mixture into your cookie scoop. Release onto your prepared baking sheet. The mixture should mostly hold its scoop form though it may be a little loose. Repeat with remaining mixture, spacing each cookie about 1.5 inches apart. Lightly wet the back of a metal spoon and use it to press, compact and shape the mixture until it becomes a thin round disk (about 1/4 inch thick). The oats need to be compacted together and touching so they bind during baking and should be shaped into a round cookie shape. The cookies will not change shape during baking so you want to shape them how you want the final outcomes to be. I find that the metal spoon for shaping starts to get very sticky with syrup after a few cookies, so it will help to fully clean the spoon after a few cookies and rewet it again so that the mixture is not sticking to the spoon.
Bake the cookies for about 15-18 minutes or until the surface is lightly browned. The longer you bake, the crispier the cookies will be but you do want to make sure the edges don't get too dark.
Remove cookies from the oven but don't attempt to move them from the baking sheet until they are fully cooled and set. If you try to remove them while they are still warm, the cookies will fall apart. The cookies will initially still feel soft when they come out of the oven, this is normal. Once they are cooled, the cookies should be firm and should peel off the parchment paper easily. Store any uneaten cookies in an airtight container within a few hours of them setting to prevent them from softening. You can store cookies for around 1 day at room temperature or around 3-4 days in the fridge. If desired, you can garnish the cookies with additional lemon zest or coarse salt before serving.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.