In the bowl of a stand mixer fitted with the paddle attachment (or in a food processor), combine the cold butter, powdered sugar, flour, and salt. Mix on medium-high speed for several minutes, until the butter is fully incorporated and the mixture resembles fine crumbs with no visible butter pieces. Test the texture with your fingers—it should feel sandy. Add the egg yolks and mix just until the dough comes together. Do not overmix.

Place the dough between two sheets of parchment paper and roll it out to a thickness of 2.5 mm. Transfer to the freezer and chill for 30 minutes.

Once firm, cut strips and circles of dough to line two 12 cm tart rings (or one larger tart ring). The strips should be slightly taller than the sides of the ring. Press the strips around the inner edge and fit a dough circle into the bottom, sealing the edges with your fingers. If the dough softens, return it to the freezer until firm. Freeze the lined tart shells for another 40 minutes before baking.

Preheat the oven to 355°F (180°C). For blind baking, place a small sheet of crumpled parchment paper into each tart shell and fill with dried beans or pie weights. Bake for 10 to 12 minutes.

Remove the weights and parchment, and continue baking for another 8 to 10 minutes, until golden. Let cool completely.

Place the white chocolate and pistachio paste in a heatproof mixing bowl. In a small saucepan, bring the heavy cream to a simmer. Pour the hot cream over the chocolate mixture, wait a few seconds, and stir until smooth. Cover and refrigerate until fully chilled, about 90 minutes.

To make the praline, preheat the oven to 320°F (160°C). Spread the pistachios on a parchment-lined baking sheet and toast for 10 minutes. Let cool completely.

In a dry skillet over medium-high heat, melt the granulated sugar without stirring. Swirl the pan gently to prevent clumping and cook until the sugar turns a deep amber. Pour the hot caramel onto a piece of parchment paper and let it cool and harden completely.

In a food processor, combine the toasted pistachios, broken caramel shards, neutral oil, and salt. Process until smooth and creamy. Set aside.

For the cream, grind the pistachios and powdered sugar together in a food processor until finely ground. In a mixing bowl, beat the softened butter with the pistachio mixture for about a minute. Gradually add the egg and mix until smooth. Pipe an even layer of the pistachio cream into each pre-baked tart shell.

Bake at 355°F (180°C) for 15 minutes, until the cream is set and lightly golden. Let cool completely, then refrigerate until chilled.

Remove the ganache from the fridge and whip with a hand whisk or stand mixer until it has the texture of soft-serve ice cream. Transfer to a piping bag and pipe a thick layer over the baked tart base. Use a spoon to create a small well in the center and fill it with pistachio praline. Cover the center with more whipped ganache, then smooth the surface with an offset spatula. Finish with a scattering of chopped pistachios and keep refrigerated until ready to serve.