To prepare the tart: Combine the cold butter, 1/2 cup of the pecans, 1/3 cup of the granulated sugar, 1 cup plus 3 tablespoons of the flour, and the salt in a food processor and process until crumbly. Add 1 of the egg yolks and 1 tablespoon of the milk and process until the dough forms a ball. Roll out the dough to 1/8-inch thick and cut into a 9-inch circle. Line an 8-inch tart pan with the dough, place on a sheet pan, and refrigerate for 1 hour.
Preheat the oven to 375 degrees F.
Bake for 10 to 12 minutes, or until golden brown.
To prepare the pecan cream: Combine the softened butter, the whole egg, the remaining 1 cup of ground pecans, 1/2 cup of the granulated sugar, the cream, and 1/4 teaspoon of the vanilla in a mixing bowl. Spread a 1/4-inch layer of the mixture in the bottom of the tart. Bake at 350 degrees F for 10 minutes, or until the pecan cream is set. Remove from the oven and set aside.
To prepare the pastry cream: Bring the remaining 2 cups milk and 1/3 cup granulated sugar to a boil. Whisk together the remaining 4 egg yolks and 1/3 cup granulated sugar in a bowl. Sift the remaining 2 tablespoons flour and the cornstarch together over the egg yolk mixture and whisk until smooth. Add the remaining 1/4 teaspoon vanilla and one third of the milk mixture and whisk until combined. Return the remaining milk mixture to a boil. Pour the yolk mixture into the milk, stirring continuously, until thickened and remove from the heat.
To prepare the tart: Cut the bananas into 1/4-inch thick slices and arrange in a single layer over the pecan cream in the tart shell. Spoon the pastry cream over the bananas and smooth with spatula. Lower the oven to 350 degrees F. and bake for 10 minutes. Remove from the oven and cool slightly, then refrigerate for at least 1 hour.
Cut the tart into 6 slices and place a slice in the center of each plate. Arrange the toasted pecans on each slice and dust with confectioners' sugar.