Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper or a silicone baking mat.
Spread the flour out onto the prepared baking sheet, leaving a 1-inch border around the edge. Toast the flour for 5 minutes, then remove the baking sheet from the oven. Gently stir the flour with a rubber spatula, then return the baking sheet to the oven. Toast the flour, stirring every 5 minutes, for another 20 minutes. The total toasting time is 25 minutes. Remove from the oven and let cool completely. Keep the oven temperature at 350 degrees F.
Line 2 baking sheets with parchment paper. On a small plate, mix together 1/2 cup of the granulated sugar with the cinnamon and set aside.
In a stand mixer, cream together the butter, brown sugar and remaining 1 cup granulated sugar until light and fluffy. Beat in the milk, vanilla and egg.
Stir together the toasted flour, baking soda, baking powder, allspice and salt in a bowl. Add the dry ingredients to the wet mixture and mix on low until just incorporated.
For each cookie, remove a heaping tablespoon of dough and roll into a ball. Roll each ball of dough in the cinnamon sugar and place onto the prepared baking sheets. With the bottom of a flat glass, gently push down on each ball of dough until the dough flattens to 1/4 inch thick. Bake until the cookies are golden brown, 10 to 12 minutes.