1 1/2 teaspoons baking soda
2 teaspoons ground ginger
1 teaspoon ground cinnamon
1/4 teaspoon salt
1 stick plus 2 tablespoons unsalted butter, softened
3/4 cup sugar
1 large egg, at room temperature
1/4 cup unsulfured molasses
Filling
6 tablespoons unsalted butter, softened
2 cups confectioners’ sugar
1 1/2 tablespoons fresh lemon juice


FIVE: Arrange the cookies in pairs on a large work surface. Spoon or pipe 1 rounded tablespoon of the lemon filling onto the flat side of half of the cookies. Sandwich with the remaining cookies, pressing them together so the filling spreads to the edge.
Make Ahead: The sandwich cookies can be stored in an airtight container between sheets of wax paper for up to 1 week.