Preheat oven to 350 degrees. Line baking sheets with parchment paper.
In a large mixing bowl, cream butter and sugar until fluffy. Add eggs, one at a time, beating well after each addition. Add molasses and beat well.
Sift together dry ingredients. Add at low speed to butter and sugar mixture and beat just until combined.
Drop batter by rounded spoonfuls onto baking sheet 2 1/2 inches apart – cookies will spread. Bake 9 to 11 minutes, rotating cookie sheets from back to front once midway through baking. Cookies should be golden brown and slightly darker around the edges when done. Watch carefully during final minutes of baking because they burn easily.
Remove from oven and let stand a minute before removing carefully to a rack. Sift powdered sugar over cookies while still warm. When completely cool, store in airtight tin or zip-top bag to freeze. Before serving, sift with more powdered sugar.
Makes 4 dozen cookies