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
6 tablespoons unsalted butter, softened
2 cups confectioners’ sugar
1 1/2 tablespoons fresh lemon juice
FOUR (filling): In the bowl of a standing electric mixer fitted with the paddle, beat the butter with the confectioners’ sugar at medium speed until light and fluffy, about 3 minutes. Beat in the lemon juice (I doubled the amount of lemon required for a more tart taste – worked out great).
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.