In a medium bowl, mix the melted butter, dark brown sugar, and ground cinnamon for the filling. Set aside.

In the bowl of a stand mixer with the paddle attachment, cream the room temperature butter and granulated sugar together for about 2 minutes until light and fluffy.

Add the egg, vanilla extract, heavy cream, baking powder, and kosher salt to the butter mixture. Mix for 1 minute, scraping the sides of the bowl to ensure even mixing.

Turn the mixer to low and gradually add the all-purpose flour until just combined.

On a lightly floured piece of parchment paper, press the dough into a rectangle approximately 15x10 inches.

Spread the prepared filling evenly over the dough, leaving about an inch at the edges.

Starting from the long edge, roll the dough tightly into a log.

Cut the rolled dough into 10 equal slices. Roll each slice into a ball and place them in the freezer for 20 minutes.

Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent sticking.

Place 5 cookie dough balls on the prepared baking sheet, ensuring there is space between them to allow for spreading.

Bake the cookies for 15-17 minutes or until they are lightly golden around the edges.

For the icing, whisk together the powdered sugar, melted butter, and 1 tablespoon of milk until smooth.

Once the cookies are completely cool, you can either dip them in the icing or drizzle it over the top.