Combine the butter, sugar, egg, lemon zest and vanilla in a mixing bowl and stir on medium speed until soft. Stop the mixer and add the flour by hand. Wrap the dough in plastic and place in the refrigerator to cool for approximately 3 hours.
To make the custard:
Combine the milk and heavy cream in a pot. Bring to a simmer on the stovetop. Meanwhile whip the egg yolks with the sugar, corn starch, vanilla and lemon. When they are well whipped and you can see peaks, add to the boiling milk/heavy cream and cook until it gets a “mayonnaise” consistency, continuing to stir while on the stove. Do not let it burn or stick to the bottom!
Put the finished custard in another container to cool and let it rest in the fridge.
Stir in the lemon marmalade.
To make the tart:
Using your fingers, arrange the shortcrust pastry in the baking pan. Fill in with the lemon custard.
Bake for 40 minutes at 350 degrees, or until the custard has become like a pudding.
Remove from the oven and let cool.
Gently remove the tort from the baking pan and add toasted pine nuts to the surface. Sprinkle with powdered sugar and the shaved lemon chocolate.