Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a bowl, whisk together flour, baking soda, ginger, cinnamon, and salt.

In another bowl, cream the butter with brown and granulated sugar until light and fluffy. Mix in molasses until combined.

Gradually add the dry ingredients to the wet mixture until well incorporated.

Drop rounded tablespoons of dough onto prepared sheets about two inches apart. Bake for 10-12 minutes until edges are golden but centers remain soft.

While cookies cool, beat together butter, powdered sugar, lemon zest, and juice until fluffy.

Once cooled, spread lemon buttercream on one cookie and sandwich it with another.