8 ounces (2 sticks) unsalted butter, room temperature
1/2 cup confectioners' sugar
1 teaspoon pure vanilla extract
Body
Line 2 rimmed baking sheets with parchment. Wisk together flour and salt. In the bowl of a mixer fitted with the paddle attachment, beat butter until fluffy, 3 to 5 minutes. Add sugar, and continue to beat until pale and fluffy, occasionally scraping down the sides of bowl, about 2 minutes more. Beat in vanilla. Add flour mixture, and mix on low speed, scraping sides if necessary, until flour is just incorporated and dough sticks together when squeezed with fingers.
Turn out dough, forming into 2 disks; wrap each in plastic. Refrigerate until firm, at least 1 hour.
Preheat oven to 325 degrees. Roll out 1 disk to a 1/4-inch thickness. Cut out shapes using desired cookie cutter, and transfer to prepared baking sheets. Reroll scraps. Repeat with remaining disk. Indent cookies with desired stamps. Refrigerate until firm, at least 30 minutes. Bake until firm and golden, 13 to 15 minutes. Let cool completely on a wire rack.
Combine brown sugar, molasses, butter, spices, and salt in a medium saucepan over low heat, stirring with a wooden spoon, until sugar is dissolved, about 10 minutes. Stir in milk. Remove from heat, and let cool.
Pour milk mixture into a mixing bowl; add baking powder and flour. With an electric mixer, and beginning on low speed and increasing to medium, beat until well combined. Divide dough in half; shape into disks. Wrap in plastic, and refrigerate overnight. Dough can be frozen up to 1 month; thaw in the refrigerator before using.