Make the cookies:

1. Preheat the oven to 350°F and line two baking sheets with parchment paper.
   In the bowl of a standing mixer, combine melted butter, sugar, egg, banana, peanut butter and vanilla. Beat on medium-high until well-combined.
2. With the mixer off, add flour, baking soda, baking powder, salt, and cinnamon, and whisk the dry ingredients together with a fork a little before turning the mixer back on lowest setting. Beat just until the dry ingredients are incorporated.
3. Add oats, cranberries, pecans, seeds, zest, and juice, and beat on lowest setting until combined. Pop the dough in the fridge for 30 minutes before baking.
4. Scoop out the dough into balls (about 1 tablespoon each), roll them with your hands then slightly flatten them on the baking sheet.
5. Bake 5 minutes, then remove from oven and use a spatula to flatten the tops again middway through baking.  Return to oven and cook 5 – 7 more minutes, until turning golden. Let cool on the pan for 2 – 3 minutes, then finish cooling on wire racks.

Make the cinnamon buttercream filling:

1. Wash and dry your mixer bowl, then beat butter on medium-high with the paddle attachment for about 5 minutes. Yes, it’s a long time, but it’s what makes the buttercream light and fluffy.
2. Turn the mixer down to low and gradually add in the powdered sugar. Continue mixing on low speed until the powdered sugar is completely incorporated. Add in vanilla, cinnamon, and half-and-half, and mix until combined.
3. Turn mixer back up to medium-high speed and beat the mixture for an additional 3-5 minutes. If needed, add in a little more half-and-half OR powdered sugar 1 teaspoon at a time if the buttercream is to dry or too . wet.
4. When the cookies are completely cool, use a knife to spread the cream filling on the flat side of half of the cookies and put the remaining cookies on top. Or, do as we did and enjoy them open faced!