Cream together the butter, brown sugar, and molasses. Beat for 2 minutes on medium speed. Scrape the sides frequently.
Add the egg and beat for another minute.
In another bowl, whisk together the dry ingredients.
Add the dry ingredients to the butter mixture. Mix just until the flour is incorporated. Do not over-beat the dough.
Divide the dough in half and wrap it in plastic wrap.
Chill the dough for 30 minutes in the freezer or at least an hour in the refrigerator. Line your cookie sheets with parchment paper.
Scoop out some dough and roll it into a ball.
Roll the dough in sugar.
Dip the glass in sugar and use the bottom to flatten out your cookies.
I cannot help myself, even though they were already rolled in sugar, I still sprinkled them with some sanding sugar. If I had my way, everything would have a sprinkling of sanding sugar on it.
Bake in a preheated 350 degree oven for 12 to 14 minutes. The tops will “feel set to the touch” according to Dorie. Cool on a rack.