Bring the beer to a simmer in a medium saucepan set over medium heat, stirring occasionally. Watch closely to make sure it doesn't foam over the sides, reducing the heat if necessary., Bring the beer to a low boil and cook, stirring often, for about 15 minutes, until it thickens and reduces to 3 tablespoons (1 1/2 ounces; see "tips," below). Set aside to cool. Note: If you sneak a taste of the reduction it will taste unpleasantly bitter, but don't be afraid; this is how it should be. Much like an extract, once mixed into the dough it will be delicious. , In a medium saucepan set over low heat, heat the butter, molasses, 2 1/4 cups of the sugar, and salt. Stir often, until the butter melts and the sugar and salt dissolve, about 10 minutes. Remove from the heat., Stir in the spices and the amber ale reduction. Allow to cool for about 10 minutes., Whisk together the flour and baking soda in a large mixing bowl. Turn the mixer to low and slowly pour in the liquid ingredients., Add the egg. Mix until well blended and a thick batter forms. Stir in the raisins and ginger., Cover the dough and refrigerate for 1 hour, until firm., Preheat the oven to 350°F. Line two baking sheets with parchment. Pour 1/2 cup sugar into a small bowl., Scoop the dough by the tablespoon and roll into balls. Roll the dough balls in the sugar to coat, then place on the prepared baking sheets, leaving 2" of space between them., Bake the cookies for 14 minutes. They'll puff up and still look soft. When the edges just begin to brown, remove them from the oven., Let the cookies rest for 5 minutes on the pan before transferring to a cooling rack. The cookies will become crisp as they cool., Store cookies in an airtight container at room temperature for up to 10 days; freeze for longer storage.