Preheat the oven to 350°For this recipe use a 9-inch tart pan with a removable bottom. Do not butter the tart pan.
Put the flour and toasted pistachios in a food processor and process until the pistachios are well ground and only a few small pieces remain. Add the sugar and salt and pulse a few times until the ingredients are well combined.
Pour the flour-nut mixture into a medium bowl and add the melted butter. Mix together with a rubber spatula until the dough forms a cohesive ball and no bits of flour remain. Using your hands press 2/3 of the dough into the bottom of a 9-inch tart pan. Press the remaining dough into the fluted sides.
Place the tart pan on a rimmed baking sheet and bake until the crust is golden brown, about 30-35 minutes. Rotate the pan halfway through the baking. Remove the tart from the oven and cool room temperature. If using the next day, cover with plastic wrap.
For the Simple Syrup
Add the sugar and water to a small saucepan. Stir together and then bring to boil. Remove the syrup from the heat and pour into a clean glass jar. Allow the syrup to cool to room temperate. The simple syrup can be stored at room temperate for a few weeks.
For the White Chocolate Lemon Pastry Cream
Place a medium sized bowl with a fine mesh strainer near the stove. Line a glass or metal pie plate with plastic wrap and set it near the stove.
Put water into a small saucepan and bring to a simmer. Place 3 ounces of chopped white chocolate in a small bowl and place it over the simmering water and melt the chocolate. Do not allow the water to boil.
In a 3-quart non-reactive saucepan combine 3/4 cup milk, the butter, lemon zest and 3 tablespoons (39 grams) of sugar. Whisk together and heat over medium heat. Heat the milk mixture until bubbles start to form around the edges of the milk and steam begins to rise from the surface.
Separate the eggs and place the egg yolks in a small bowl. Save the egg whites for a cake, macarons or Swiss Meringue buttercream.
In a medium bowl whisk together the cornstarch and the flour and 2 tablespoons (26 grams) of sugar. Add 1/4 cup of milk, whisk together and then whisk in the egg yolks.
Remove from heated milk mixture from the heat and slowly add half of it to the egg mixture whisking the entire time to temper the eggs. Pour the egg-milk mixture back into the saucepan with the milk and over the medium heat whisk continuously until the mixture thickens and has started to boil. Immediately remove from the heat.
Strain the pastry cream through a fine mesh strainer into a medium sized bowl. Add the melted white chocolate and stir until fully incorporated. Add the lemon juice and stir until well combined.
Pour the pastry cream into the plastic-lined pie plate, cover with another piece of plastic wrap lightly pressing it into the surface of the pastry cream and place it in the refrigerator to cool.
For the Raspberry Glaze
Strain the raspberry jam to remove the seeds. Add 2 tablespoons of simple syrup.
Raspberry Tart Assembly
Scrape the cooled lemon white chocolate pastry cream into the cooled pistachio tart crust. Smooth the surface with an offset spatula. Refrigerate until ready to decorate with the raspberries.
Arrange the raspberries in any way you choose – circles, straight lines or simply pour the berries on stop. Brush the berries with the raspberry glaze. Sprinkle with chopped toasted pistachios. Refrigerate until ready to serve.
Notes
The pistachio tart crust and the pastry cream can be made 1-2 days in advance. The tart can be assembled a few hours before you are ready to serve.I listed the raspberries in ounces and grams because fresh raspberries are usually sold in plastic clam shells with the amount listed in ounces. The pint size green pulp berry trays usually hold 8-10 ounces.