Heat the oven.
Set the oven to 350°F. Line a baking sheet with parchment. The oven should be fully hot before baking.
Mix the dry ingredients.
Stir the flour, baking soda, salt, and ginger in a bowl. The mix should look even, with no clumps.
Cream the butter and sugar.
In another bowl, mix the butter and brown sugar until smooth and fluffy. It should look lighter and spread easily.
Add egg and molasses.
Mix in the egg first. Then add the molasses. The dough will turn dark and glossy.
Combine wet and dry.
Add the dry mix to the wet mix. Stir just until the dough comes together. It should feel soft and slightly sticky.
Roll in sugar.
Scoop dough into balls about the size of a walnut. Roll each one in granulated sugar until coated.
Bake.
Place dough balls on the baking sheet with space between them. Bake for 8–11 minutes. The tops should crack, and the centers should look set but soft.
Cool.
Let the cookies rest on the pan for 5 minutes. Then move them to a rack. They will firm up as they cool.