1 1/2 sticks butter (12 tablespoons)
1 cup dark brown sugar, firmly packed
1 large egg
1/4 cup unsulphered molasses
1 strong tablespoon grated lemon zest
2 1/2 cups flour
2 teaspoons baking soda
1/2 teaspoon salt
1 tablespoon plus 2 teaspoons ground ginger
1/3 cup granulated sugar
2 teaspoons freshly squeezed lemon juice
Preheat oven to 350 degrees. With an electric or stand mixer, cream butter and brown sugar until light and fluffy. Scrape down bowl during the process. Beat in the egg until incorporated, then add molasses and lemon zest. Beat until blended.
Whisk together dry ingredients and add, in batches, to the creamed mixture, scraping the bowl to ensure all the ingredients are incorporated. Chill dough for half an hour.
In a small bowl, blend granulated sugar with 1 teaspoon lemon juice, stirring to ensure the juice is fully distributed. Add the second teaspoon, again stirring to fully cover each granule of sugar. (If you have extra zest, toss it in too.)
Using a small ice cream scoop, dip out cookies, scraping the bottoms flat. Roll each cookie in the lemon sugar, place on a cookie sheet and bake until the cookies are puffy and golden, no more than 12 minutes. Allow to cool for a minute on the cookie sheets before removing to fully cool on a rack.