1 Cut butter in pieces. Mix flour, sugar, butter, 1 pinch salt and 1-2 tablespoons cold water. Knead using the dough hook of a hand mixer or knead by hand until smooth.
2 Roll out dough between 2 sheets of plastic wrap to about 30 cm (or approximately 12 inches) in diameter. Place rolled dough into a springform pan or greased tart pan (24 cm or approximately 10 inches in diameter), forming a 3 cm (approximately 1 1/4-inch) high edge. Refrigerate for 30 minutes.
3 Meanwhile, rinse sweet potatoes and cook until soft in plenty of boiling water for about 35 minutes. Peel potatoes and press through a potato ricer into a bowl.
4 Pierce dough with a fork several times. Cover bottom with a piece of parchment paper and add beans. Position an oven rack at the lowest position. Bake the pie shell in a preheated oven at 180°C (convection oven 160°C, gas mark 2-3) (approximately 350°F/convection 325°F) on the lowest rack for 15 minutes.
5 Remove beans and parchment paper and continue baking for 5 minutes.
6 Mix sweet potatoes with eggs, condensed milk, maple syrup and cinnamon.
7 Pour sweet potato mixture into the pre-baked crust and bake at 180°C (convection oven 160°C, gas mark 2-3) (approximately 350°F/convection 325°F) on the second shelf from the bottom until the filling is set, 40-45 minutes. Let cool on a rack before serving.