Mix slowly the butter with flour and confectioners sugar, using your fingers. Don't overmix.
When is almost done, add the beaten egg and mix in a little bit.
Wrap in a cling film and set in the fridge for at least 1 hour
On a lightly floured surface, roll the dough out into an 34 cm circle, for a 28 cm tart pan (preferably with a removable bottom)Flouring a rolling pan and rolling the dough loosely around it, then unrolling it into the pan. Brush away the excess flour on the surface. With a knife, trim the edges of the pastry to fit the tart pan.
Wrap in a cling film and set in the freezer until firm, about 20 -30 minutes
Preheat oven to 200°C ( medium heat ) and place rack in the center.
Put aluminum foil against the crust, covering the edges to prevent them from burning.Fill with uncooked rice or beans.
Bake for about 30 minutes longer until golden brown and dry. Transfer to a wire rack and let cool completely.
Toffee ( caramel )
In a large heavy bottomed saucepan, combine all ingredients.
Cook over medium heat, stirring occasionally.
Allow to come to a boil, switch the heat to low and cook until the mixture becomes a golden color and its texture is changed. You must stirring frequently, about 20 minutes!
Pour the mixture over the cooled tart crust.
Garnish with banana slices and let to chill at least 1 hour