Preheat the oven to 350 degrees F. Line 2 baking sheets with parchment paper.
In the bowl of an electric mixer with a paddle attachment, cream together the sugar, lemon zest and butter on medium speed until fluffy, about 5 minutes. Then add, individually, the egg, molasses and lemon juice and mix well.
While that is mixing, sift together in a large bowl the flour, ginger, cinnamon, baking soda, allspice, cloves, nutmeg and salt. Reduce speed to low and add the flour mixture slowly to the butter mixture. Combine well. The batter should be a bit sticky but workable in your fingers and very light.
Scoop out the batter in heaping 1 tablespoon sizes and lightly roll into balls. Arrange on the sheets, allowing at least 1 1/2 to 2 inches in between. Make a deep crater in the middle of each ball with your finger or the end of a wooden spoon. The cookies will spread as they cook and the crater will leave a dent to hold the curd.
Bake for 12 minutes and cool completely on a rack. While the cookies are still warm, lightly re-press the dent if it has lost its shape during the baking process. Store until serving. To serve, dust with confectioners' sugar and fill with cooled lemon curd just before serving.
My favorite holiday cookie was created by my dear friend Gary, who is the daddy of my Goddaughter: Ginger cookie with lemon curd; two things I love. The cookie itself is irresistible. When I put the lemon curd on it, I'm in trouble! This cookie is light and delicious and very enticing on a holiday platter. If you want to make it ahead simply store the plain cookies in an airtight container and dust with powdered sugar and fill with curd just before serving.