In a large mixing bowl, combine packed brown sugar and canola oil, beating them together until well blended and smooth, about 2 minutes. Then, add the large egg and molasses to the mixture, continuing to mix until everything is fully incorporated.

In a separate bowl, whisk together the all-purpose flour, ground ginger, baking soda, ground cinnamon, ground cloves, and salt. Gradually add this dry mixture to the wet ingredients, stirring gently until just combined.

Cover the mixing bowl tightly with plastic wrap and refrigerate the dough for at least 2 hours.

Preheat your oven to 350°F (175°C) while the dough chills. Prepare two baking sheets by lining them with parchment paper.

Once the dough is chilled, use a tablespoon or cookie scoop to roll the dough into 1-inch balls. Gently roll each ball in confectioners' sugar until fully coated, then place them spaced about 2 inches apart on the prepared baking sheets.

Place the baking sheets in the preheated oven and bake for 10-12 minutes until the tops are set and begin to crack.

While the cookies cool, make the vanilla bean buttercream filling. In a mixing bowl, beat the unsalted butter until fluffy, approximately 3-4 minutes.

Once the cookies are fully cooled, take one cookie and spread about a tablespoon of the buttercream filling on the flat side. Top with another cookie to create a sandwich.