First, make the pastry cream.

In a small bowl, whisk together the egg yolk, sugar, cornstarch, and vanilla until smooth and creamy.

In a small pot, heat the milk and cream together until almost boiling. Take off heat, and slowly drizzle into the egg mixture as you whisk constantly.

Once it's all incorporated, pour the whole mixture back into the pot, and heat until the mixture thickens and resembles thick pudding.

Pour the pastry cream into a shallow bowl, cover with plastic wrap, and refrigerate.

Next, make the crust. In a large bowl, combine the flour, sugar, baking powder, and salt.

Using a pastry blender, cut in the butter until it resembles coarse sand.

Make a well in the middle of the pastry, and pour in the ice water and egg yolk {save the white for later}; work it in with your hands until no longer overly wet and sticky. If the dough is overly crumbly, add in the heavy cream a little at a time until the pastry is relatively pliable and no longer floury.

Pat into a circle, wrap in plastic wrap, and refrigerate for about 30 minutes.

Lightly flour a clean work surface, and use a rolling pin to roll out a large rectangle with the dough. Divide the dough evenly among 6 tartlet pans {you can also use one large tart pan}, pressing down the bottom and up the sides. Prick the bottoms with a fork, then top with a piece of foil. Fill the crust with pie weights or dry beans. Place in fridge for another 10 minutes.

Preheat the oven to 350F.

Bake tartlets for 15 minutes. Remove foil and weights, spoon 1-2 tablespoon of jam in the bottom of each, and brush the sides of the crust with the reserved egg white. Bake for 10-12 more minutes, until lightly golden but not brown. Set aside to cool.

When ready to assemble, grab the pastry cream from the fridge. Whisk until smooth and creamy, then add in the pistachio cream and mix until well incorporated and silky. Add in a few drops of food coloring if desired.

In a medium bowl, using a hand mixer, beat the butter for the buttercream until smooth. Add in the powdered sugar, vanilla, salt, and cream, and mix until a fluffy frosting forms.

Gently fold the buttercream into the pistachio pastry cream.

Divide the cream evenly among the prepared tartlets, then refrigerate at least 2-3 hrs but optimally overnight.

Just before serving, top tarts with raspberries, white chocolate, and pistachios. Serve chilled!