Martha and Jeff Daniels bake brown butter cookies with a decorative faux-bois design.
Heat butter in a medium saucepan over medium heat until lightly browned, 3 to 5 minutes; remove from heat and set aside to cool.
In a large bowl, whisk together flour, salt, and cardamom; set aside. In the bowl of an electric mixer fitted with the paddle attachment, cream together browned butter and both sugars until light and fluffy. Gradually add flour mixture and mix until just combined. Turn dough out onto work surface and divide into two equal pieces. Form each piece into a rectangle.
Preheat oven to 350 degrees.
Working with one piece of dough at a time (and keeping remaining piece covered with plastic wrap), place dough on a nonstick baking mat and loosely cover with plastic wrap. Roll dough out between baking mat and plastic wrap to form a large rectangle, 1/16-inch-thick. Remove plastic wrap and place a faux-bois mat on dough, pattern side down. With rolling pin, lightly roll over mat to imprint dough.
Carefully remove faux-bois mat. Trim edges of dough and reserve scraps. Cut into four 6-by-4-inch rectangles or two 12-by-14-inch rectangles. Carefully transfer nonstick baking mat to a baking sheet and transfer to freezer; freeze until dough is chilled, about 10 minutes. Repeat process with scraps and remaining piece of dough.
Once dough is chilled, position rectangles so that they are 1 inch apart. Transfer to oven and bake until edges are slightly brown, 10 to 12 minutes. Transfer cookies to a wire rack and brush with maple syrup; let cool completely.