Preheat your oven to 350°F (175°C) and prepare by lining your baking sheets with parchment paper.

Whisk together the flour, baking soda, salt, and cinnamon in a large bowl until well combined.

Combine the melted butter, brown sugar, and granulated sugar in another bowl. Mix until smooth.

Add the egg, vanilla, mashed bananas, and sour cream to the sugar mixture. Stir until combined.

Fold in your dry ingredients just until everything is combined.

Scoop large portions of dough onto your prepared baking sheets. Flatten slightly with the back of a spoon.

Bake for 11–14 minutes or until the edges are set and the cookies are lightly golden. Cool completely on a wire rack.

Beat together the cream cheese, powdered sugar, vanilla, and milk until smooth to create the glaze.

Glaze the cooled cookies generously with your cream cheese mixture. Let set at room temperature before serving.