Preheat oven to 180°C.
Spray the bottoms and sides of the mini muffin tins with cooking spray.
For the dough: In a food processor, pulse pecans with the sugar, salt, and flour, until the nuts are ground and the ingredients are combined. Add in butter and pulse until dough resembles coarse meal. Slowly pour in ice water through the feed tube, pulsing, until the dough comes together. Remove from processor bowl onto clean work surface sprinkled with flour.
Form dough into a ball and divide evenly into 24 pieces. Roll each piece into a ball and evenly press into each cup, until the bottom is covered. If the dough is sticky, dip your finger in flour first.
Bake 15 to 18 minutes, until the crusts are very golden. Check periodically to make sure they don't get too brown.
Meanwhile, make the filling: In a medium bowl, whisk the egg and yolk with the corn syrup, sugar, pumpkin and vanilla. Stir in the chopped pecans.
Remove dough from oven and spoon one tablespoon of the filling into each cup. Top each with one pretty pecan half. Return the pans to the oven and continue baking, for 12 to 15 minutes more, until the pumpkin filling is set. Allow to cool before removing from the pans.