California Walnut Blackberry Tart

Combine flour and walnuts in the bowl of a food processor. Process until walnuts are finely ground with the flour.

Place butter and sugars in the bowl of a standing mixer fitted with the paddle attachment. Cream until light and fluffy.

Add egg and then egg yolk, mixing each until fully incorporated before adding the next.

Add processed walnut flour, baking powder, and salt. Mix until dough just comes together.

Scrape dough onto a lightly-floured work surface. Divide into 2 equal portions, about 16 ounces (455g) each, and shape into flat, round disks. Wrap each disk tightly in plastic wrap and refrigerate for at least 30 minutes.

Finely grind walnuts to a powder using a food processor or blender, and set aside. Cream butter and sugar in the bowl of a standing mixer fitted with the paddle attachment. Mix in the eggs one at a time. Mix in ground walnuts, vanilla, salt, and cardamom. Set aside.

Whisk together sugar and cornstarch in a medium bowl to get rid of any lumps. Whisk in egg yolks and a few tablespoons of the cold milk. Place remaining milk in a small saucepot with vanilla and cardamom. Bring to a simmer over medium heat. Temper hot milk into egg yolk mixture and then return entire mixture back to the pot. Continuously whisking over medium heat until thickened, about 3 minutes. Whisk in butter until completely emulsified. Transfer to a shallow container or baking sheet lined with plastic wrap. Press plastic wrap over the top and refrigerate until chilled.

Working with one portion of dough at a time (the other portion can be frozen for another time), set a dough disk on a floured work surface. Using a rolling pin and adding more flour as needed underneath and on top of the dough to prevent sticking, roll out to a 13-inch circle about 1/8 inch thick.

To transfer dough to the tart pan, carefully roll dough around the rolling pin, then unroll over the pan. Dust off any excess flour. Press dough gently yet firmly into the edges and up the sides of the pan. Using a paring knife or small offset spatula, trim dough overhang so it is level with the top of the pan. Freeze tart shells for at least 30 minutes.

When ready to bake, preheat the oven to 350° F. Line tart shell with parchment paper and fill with beans, sugar, or rice. Transfer to a sheet tray and blind bake until golden brown around the edges, about 30 minutes. Remove parchment and weight, and return to oven and bake until the bottom is golden brown, too, about 5 – 10 minutes.

Remove fully baked tart shell from oven and spread walnut frangipane over the bottom. Return to the oven and bake until puffed and golden, about 25 minutes. Remove from oven and cool completely before assembling.

Place all ingredients in the bowl of a stand mixer fitted with the whisk attachment and whisk until medium stiff peaks form. Transfer to a pastry bag fitted with a large round tip.

Remove pastry cream from refrigerator. Transfer to the bowl of a standing mixer fitted with the paddle attachment. Cream until smooth. Spread in an even layer over the top of walnut frangipane. Toss blackberries with melted nappage/jelly to glaze. Alternate piping a row of whipped cream with a row of blackberries all the way across the tart. Garnish with mint leaves and edible flowers, if desired.