Flaky saltsuch as Maldon or fleur de sel (optional)
Line a large baking sheet with parchment paper.
In a large bowl, whisk together the coconut sugar and egg until combined. Whisk in the banana, vanilla, cinnamon, and salt.
Add the peanut butter and continue to whisk until the dough is smoothly and evenly combined. It will be thick, wet, and sticky. If the dough becomes too hard to whisk, switch to a rubber spatula or wooden spoon. Stir in the chocolate chips. Place the dough in the refrigerator to chill for 30 minutes. Place a rack in the center of the oven and preheat the oven to 350 degrees F.
With a cookie scoop or spoon, scoop the dough into 2 tablespoon-sized mounds and place on the prepared baking sheets, leaving 1 1/2 inches of space between each. Sprinkle each cookie with salt, if using. Return any unscooped dough to the refrigerator to chill while the first batch bakes.
Bake for 11 to 12 minutes, until the cookies are turning golden at the edges but still look underdone in the center. Place the baking sheet on a cooling rack and let the cookies cool on the sheet for 2 minutes. Gently transfer the cookies to the rack to cool completely (if the cookies are still too delicate to transfer, simply slide the whole piece of parchment with the cookies directly onto the cooling rack). Repeat with the remaining dough, ensuring that you allow the cookie sheets to cool completely between batches.
TO STORE: Store leftover cookies at room temperature in an airtight container for up to 4 days.
TO FREEZE: Place cookies in an airtight freezer-safe storage container or ziptop bag in the freezer for up to 3 months.