Preheat oven to 350 degrees F. Line two large baking sheets with parchment paper or a silicone baking mat.
In a large bowl of an electric mixer fitted with a paddle attachment, beat butter and sugars together until light and fluffy. Whip in egg, vanilla and molasses until mixture turns a light brown color, about 1-2 minutes. Stir in flour, baking soda, cinnamon, ginger, salt, cloves and nutmeg until just combined.
Scoop cookie dough into 2-teaspoon-sized dough balls. Roll in your hands to smoothen. Coat each ball in granulated sugar. Place on prepared baking sheets, about 1 inch apart.
Bake for 6-8 minutes, or until golden with a soft center. Let cookies cool 5 minutes on the baking sheet before transferring to a wire cooling rack.
For the buttercream filling:
Whip butter, sugar, vanilla and heavy cream into a thick, smooth buttercream frosting. Spread 1/2 tablespoon of buttercream onto one cookie. Top with another cookie. Repeat with remaining cookies.
Serve or store in an airtight container (refrigerated) for up to three days.