In a large bowl, combine the flour and sugar. Drop in the diced butter.
Work the butter into the flour with a pastry cutter or by rubbing the mixture quickly between your palms until the mixture ressembles a crumble.
Add the water, work it in slowly with your fingers to form a dough. Divide the mixture in 2, flatten into disks, wrap in plastic wrap and refrigerate for 30 minutes.
Take 1 disk of dough out of the fridge (each disk will make 4 tarts for 8 total). Divide it in 4 and roll each quarter into a round so that it is larger than your 3 ¾" fluted tart pans (similar to these on Amazon). Fit each round of dough into each pan and trim the excess. Repeat with the remaining dough to make 8 tart shells total.
Chill the tart shells while you make the filling.
Preheat the oven to 400 °F (200 °C).
To make the filling
In a deep bowl with a hand blender, mix together the pumpkin, sugar, maple syrup, cream, egg, and spices.
Divide the filling between the 8 unbaked shells. Place the pans on a large baking sheet.
To bake the tarts
Place the tarts on a baking sheet. Bake the tarts on the bottom rack of the preheated oven for about 30 minutes. The edges should begin to brown and the filling should appear set.
Prepare the whipping cream, by whipping the cold cream until it forms soft peaks, then adding in the vanilla and icing sugar, and whipping to firm peaks.
Dollop the cream on the tarts or pipe to decorate them.