For the crust, place the pistachios and sugar in a food processor. Pulse until the nuts are finely ground. Add the flour mixing to combine. Pulse the butter until the mixture resembles pea-sized crumbs. Add the yolk. With the motor running, pour in the water until the dough just starts to form.

Gather the dough and pat into a disc. Wrap with plastic wrap and chill in the refrigerator until firm, at least 1 hour or up to 2 days.

Preheat the oven to 375 degrees F. On a lightly floured work surface, roll out the dough into a 15-inch x 5-inch rectangle. Place the dough in the pan pressing into the bottom and sides. Trim the excess dough. Prick all over with a fork. Chill in the freezer for 20 minutes.

Place parchment paper over the tart and fill with pie weights. Bake for 10-12 minutes until the edges are set. Remove the parchment and pie weights and bake for an additional 12-15 minutes until light golden brown. 

For the filling, whisk together the eggs, sugar, heavy cream, lemon juice and zest. Pour into the tart shell, and bake until the filling is just set, about 18-22 minutes.

Cool the tart completely on a wire rack. Transfer to the refrigerator to cool for at least 2 hours or overnight.

For the candied lemon slices, bring a small saucepan of water to a boil. Blanch the lemons for 5 minutes. Use a slotted spoon to shock the lemon slices in ice water. Drain and pat dry with paper towels.

In a large skillet, bring the sugar and 1 cup water to a boil letting the sugar dissolve. Add the lemon slices, lower the heat and simmer the lemons for about 30 minutes until they look translucent. Cool completely in the syrup. Store in an airtight container in the refrigerator up to 2 days.

Decorate the tart with confectioners’ sugar, chopped pistachios and candied lemon slices.

Store covered in the refrigerator.