Brightly colored slices of candied kumquat add a pop of spring citrus flavor to pastry cream tartlets.
Preheat oven to 400 degrees. Spray 36 1 1/4-inch round fluted tartlet pans with nonstick cooking spray, working in batches if necessary, and set aside.
On a lightly floured work surface, roll out pate brisee to a scant 1/4 inch thick. Using a 2-inch round cutter, cut out 36 rounds. Fit each round into a prepared tartlet pan; trim as necessary. Place on a baking sheet and transfer to freezer until chilled, 10 to 15 minutes.
Weight down each tartlet with a second 1 1/4-inch round fluted tartlet pan. Transfer to oven and bake for 8 to 10 minutes. Remove second tartlet pans and continue baking until golden brown, 2 to 3 minutes more. Let tartlets cool completely in pans before removing.
Fill each cooled tartlet with pastry cream and top with candied kumquats; serve.