1. Whisk together flour, spices, baking soda, and salt in a medium bowl
2. Beat butter, brown sugar, and molasses until fluffy
3. Add egg and beat again until smooth
4. Slowly mix in dry ingredients until dough forms
5. Divide dough, wrap in plastic wrap, and chill for 1 hour
6. Preheat oven to 350°F and line baking sheets with parchment
7. Roll out dough to ¼ inch thick on floured surface
8. Cut into shapes with cookie cutters
9. Place on baking sheet and bake for 9–10 minutes
10. Cool on sheet 5 minutes, then transfer to wire rack
11. Mix royal icing ingredients until thick and glossy
12. Pipe icing onto cooled cookies and decorate as desired