Cut butter into small cubes and chill for 5-10min. In a bowl, whisk together flour, spices, baking powder and soda, and salt together. Set aside.
In a food processor, process the turbinado sugar for 30 seconds. Sugar should be finer in texture but some pieces may be larger than others. Add cold butter and process 30 seconds more, scraping down sides of bowl as needed. Then add egg and process 10-20 seconds until incorporated, scraping down sides as needed.
Add flour mixture and process until no dry flour remains, stopping to scrape down sides of bowl as needed to incorporate. Remove dough and knead in a bowl with a spatula to ensure no dry pockets remain.
Place dough ball in between two large sheets of parchment paper. If you want perfect lines, you can trace out a 12 x 18in rectangle before hand to guide your rolling. Roll out dough between sheets to about 3/8in thick. Remove top sheet and cut into rectangle cookies, about the size of a biscoff cookie or 1.5in x 3in. Place cut cookies onto baking sheet lined with parchment paper and freeze for 30min or chill for 1hr.
Preheat oven to 300℉ and baking cold cookies for 30-32 minutes. Let cookies cool to touch then place onto wire rack to cool completely. Whisk together icing ingredients until smooth. Ice cool cookies and decorate with sprinkles. Let icing dry for an hour or overnight. Store cookies covered for up to a week.