Preheat oven to 350 ℉. Line two cookie sheets with parchment paper.
In a large bowl, combine the egg, almond butter, maple syrup, melted coconut oil, and vanilla extract. Whisk until creamy.
In a separate medium bowl, combine the oats, oat flour, coconut sugar, cinnamon, baking soda, and sea salt. Stir to blend.
Add the dry ingredients to the bowl with the wet ingredients, and stir or beat until a cookie dough is formed.
Using a cookie scoop or large spoon, gather two tablespoons and drop the dough into balls on the cookie sheet, spacing at least 3 inches apart (cookies will spread). Bake for 10 minutes. Allow the cookies to cool on the cookie sheet for about 10 to 15 minutes before transferring to a wire rack to cool completely.
Meanwhile, make the frosting. In a medium or large bowl, combine the softened butter and powdered monk fruit. Use a hand beater to blend until fluffy, about 30 seconds to 1 minute, intermittently scraping down the sides of the bowl and beating again until needed. Add the vanilla extract and beat again until just incorporated.
To make the cream pies, spoon frosting on top of one cookie near the edge and place a second cookie on top, pressing gently. Continue to do this until all of the cookies have been sandwiched together.
Store cookies at room temperature for up to 3 days, or int he refrigerator for up to 1 week. Frosting will harden when chilled, but will still be delicious!