Preheat oven to 350º and prepare two large sheets by lining them with parchment paper or Silpat. The sheets can be oiled if you prefer.

In a large bowl, combine the flour, cream of tartar, baking soda, salt, cinnamon and nutmeg and whisk together to combine well.

In the bowl of a stand mixer, or other large mixing bowl, cream together the butter, sugars and molasses.

Beat in the egg and pumpkin

Add the flour mixture in approximate thirds and beat until well combined.

Chill the dough for about 2 hours, until very firm. You can keep it in the fridge for up to a week before baking.

Using a medium cookie scoop [1 & 1/2 tablespoons], portion the cookies, and roll them into smooth balls. Work quickly, as this is a soft dough and it will get messy if it gets warmed up very much.

Combine the topping ingredients and roll each cookie in the mixture, and place on the prepared sheets. Dip a flat bottomed drinking glass in the sugar mixture and flatten each cookie to a 2 inch diameter.

Bake two sheets at a time, for 12 minutes, until the cookies are browned at the edges.

Cool briefly on the pans, and then remove to a cooling rack.

Repeat until all of the cookies are baked - you will have about 4 dozen individual cookies.

Beat together the butter and cream cheese [make sure they are very soft or the filling will be lumpy], then add the brown sugar and beat for 1 minute.

Beat in the confectionery sugar, 1 cup at a time, until very smooth.

Beat in the cream [you can use milk or half and half] a bit at time until you have a spreadable consistency.

Spread the filling on half of the cookies and top each one with another cookie, squeezing together very lightly.

They may be stored at room temperature for 24 hours, and refrigerated after that. Bring back to room temperature before serving.