Line a sheet pan with parchment paper and set it aside.

Make the Dough: In a medium bowl, whisk together the flour, baking soda, baking powder, cinnamon, and salt. Set aside.

In a stand mixer bowl with the paddle attachment, cream together butter, coconut oil, maple syrup, and dark brown sugar until fluffy. Add vanilla, egg, and egg yolk. Mix until combined.

Gradually add the dry ingredients to the wet mixture, mixing until just combined. Cover the bowl with cling wrap and set aside.

Make the Cinnamon Filling: Mix brown sugar, butter, and cinnamon in a small bowl until smooth.

Assemble and Chill: Scoop out 20 tablespoon-sized dough balls onto the prepared sheet pan. Add a small amount of cinnamon filling to each ball. Top with another 20 dough balls to make sandwiches. Gently press down to flatten.

Chill the cookies in the freezer for at least an hour.

Bake the Cookies: Preheat the oven to 350°F and line two baking sheets with parchment paper. Divide the dough between the sheets, leaving space between each. Bake for 12-14 minutes, rotating the trays halfway through.

Remove from the oven and gently flatten the cookies. Transfer to a wire rack to cool.

Make the Icing Glaze: Mix powdered sugar, cinnamon, salt, and almond milk until smooth. Spread about 2 teaspoons of icing on each cookie, leaving a border. Allow the icing to set before storing.