How to Make It
Prepare the dough: Pulse flours, baking powder, cinnamon, salt, and nutmeg in a food processor until combined. Add butter; pulse until mixture looks like small peas.
Whisk together honey, molasses, milk, and vanilla in a small bowl. Gradually add honey mixture to flour mixture, processing just until combined, about 2 minutes. Wrap dough in plastic wrap, and chill 2 hours or up to 2 days.
Preheat oven to 350°F.
Unwrap dough, and place on a lightly floured surface. Roll dough out into a 10- x 8-inch rectangle. (You also can make 2 [5- x 4-inch] rectangles.) Cut dough into 20 (2-inch) squares.
Place dough squares on 2 parchment paper–lined baking sheets. Using dull end of a wooden skewer, decoratively dot cookies (do not pierce). Use a graham cracker as a template, if desired.
Bake at 350°F 6 minutes. Cool cookies completely on baking sheets on wire racks, about 20 minutes.
Prepare the filling: Spread raspberry sorbet in an 11- x 7-inch rimmed baking sheet lined with parchment paper. Freeze 30 minutes. Spread vanilla frozen yogurt over raspberry sorbet; freeze 30 minutes. Spread mango sorbet over vanilla frozen yogurt; freeze until all layers are firm, about 30 minutes.
Cut sorbet mixture evenly into 10 rectangles. Sandwich 1 rectangle between 2 cookies; repeat with remaining sorbet mixture and cookies. Wrap each sandwich in plastic wrap, and freeze until ready to eat.