Whisk together flour and baking powder in a bowl. Pulse pecans, confectioners' sugar, salt, nutmeg, and cardamom in a food processor until finely ground. With a mixer on medium speed, beat pecan mixture, butter, and granulated sugar until fluffy, about 6 minutes. Beat in vanilla and egg. Reduce speed to low and beat in flour mixture. Divide dough in half; shape into disks. Wrap in plastic and refrigerate until firm, at least 1 hour and up to 1 day.
Preheat oven to 375 degrees. Let dough stand at room temperature until pliable. Working with one disk at a time, roll out dough between 2 pieces of lightly floured parchment to 1/8 inch thick. Refrigerate 20 minutes. Cut out rounds with a 2-inch cutter. Cut out centers of half of rounds with 1-inch cutters in different shapes, rerolling scraps once.
Arrange cookies 1 inch apart on parchment-lined baking sheets. Bake, rotating sheets once, until pale golden, 6 to 8 minutes. Transfer cookies to wire racks; let cool completely.
Meanwhile, heat marmalade in a saucepan over medium heat until reduced to about 2/3 cup, about 10 minutes; let cool.
Sift confectioners' sugar over rounds with cutout centers and shapes. Spread about 3/4 teaspoon jam on flat side of remaining rounds, then sandwich together. Cookies can be stored in an airtight container up to 1 week.