Tiramisù tart

I have made many cakes, but this is one of my favourites. I would call it fantastic: crisp underneath, soft and creamy on top, and definitely worth trying. It takes a little work, but the result is rewarding.
You can make the pastry the day before and fill it the following day.

INGREDIENTS FOR A 30 CM TIN
BASE
300 g '00' flour
100 g sugar
100 g butter
1 egg plus 1 yolk
1 teaspoon baking powder
1 sachet vanillin
CREAM
Nutella as needed
2 egg yolks
100 g sugar
3 small packets Pavesini biscuits
250 g mascarpone
150 g fresh whipping cream
1 large cup coffee with 1 tablespoon sugar
Unsweetened cocoa powder
I prepare the shortcrust pastry.
On the worktop, I put the flour and sugar, then add the whole egg and a yolk, the baking powder and vanillin.
I break up the eggs with a fork and add the butter.
I work quickly to form a block, wrap it in cling film and refrigerate for at least 1 hour.
I line a cake tin with baking parchment.
I roll out the pastry, leaving a rim at least 2 cm high, and prick with a fork.
I blind bake it, covering the pastry with another sheet of baking parchment and pressing it into place.
I cover with dried beans, rice or whatever suitable weights are available to prevent bubbles during baking.
I bake at 170°C for 20 minutes, remove the paper and beans, then bake for another 10 minutes until evenly coloured.
The coffee I prepared and sweetened has cooled.
I take out the tart base and cover it evenly with Nutella.
I let it cool completely.
I prepare the filling.
I whisk the egg yolks with the sugar.
When pale and fluffy, I add the mascarpone.
I continue whisking.
I whip the cream in a container I have kept in the freezer.
I add it gradually to the mascarpone cream.
I fold gently upwards from the bottom until incorporated, then refrigerate.
I quickly dip the Pavesini in the coffee and place them on the tart base.
I cover the whole base.
I take the cream from the fridge and gently spoon it onto the tart.
I spread it without making the surface too flat.
I refrigerate the tart for at least 3 hours. Just before serving, I dust with unsweetened cocoa powder.