In honor of Pi Day, I knew I had to do a pie or a tart of some kind. So I went with the tart route, and made some mini pistachio-lemon tarts. The flavor combination was inspired by the lemon-pistachio brioche we sell at Milk Bar, but also my need to get rid of an excess of pistachio mousse I had made for the mille crepe, and an excess of lemons I got from a family friend the green coloration is another nod to St. Patrick’s Day, since why not? Got to stay festive! So with any lemon tart, there has to be a lemon curd or custard of some kind. I don’t care who you are or what you say, lemon curd is the BEST way to impart lemon flavor in a dessert. It carries the acidity of the lemon but in a palatable platform. I like how the lemon and pistachio contrast each other, because one is bright and zesty, while the other is salty and almost smoky.

For the different components, we have a pistachio pate sucre as my crust, lemon curd as the base, pistachio mousse on top, cubes of lemon-gold leaf gelee(for that St. Patrick’s Day flair), and tempered pistachio bark disks. Yeah, there’s a lot of things that went into this dessert (because I have a lot of lemons to kill). I’d say the most technically challenging part of this dessert would either be the pate sucre(since you have to roll it out thinly and make sure it’s baked properly or the tempered chocolate disks(just for the technicality of it and making sure that you can get the pistachios sprinkled on top before the chocolate itself sets).

Makes 4 individual tarts:
For the pistachio pate sucre:
2/3 cups all-purpose flour + more for rolling
1/3 cup finely ground pistachios
1 stick unsalted butter, cold and cubed
1/3 cup granulated sugar
2 tablespoons cold water
a pinch of salt
1/4 teaspoon spirulina powder
1 teaspoon vanilla extract

Blitz together the ingredients to form a dough. Chill down for at least 20 minutes. Roll out on a floured surface to about 1/16th an inch thickness. Lay out 4 crumpet tins onto a lined baking sheet. Cut out 4-inch rounds and place into the bottoms of lightly butter-lined crumpet tins. Cut out and press in 2-inch strips of the dough along the sides of the tins, taking off any excess with a paring knife. Prick the bottom of the tart. Weigh down with parchment and baking weights. Bake at 400 degrees F for 15 minutes, then remove the weights and parchment and continue baking for another 5 minutes at 350 degrees F, just to brown the shells. Cool completely before unmolding.

For the lemon-gold leaf gelee:
Juice from 2 lemons
1/4 cup water
3 tablespoons agar agar
1 tablespoon granulated sugar
a pinch of salt
gold leaf

Combine all of the ingredients except for the gold leaf, and bring to a simmer until there is about 1/4 cup of liquid left. Pour into a small, shallow container. Add in gold leaf and stir to scatter throughout the gelee base. Refrigerate until firm, and cut into small cubes.

For the lemon curd:
3 lemons
2 egg yolks
3 tablespoons granulated sugar
4 tablespoons unsalted butter
1 tablespoon cornstarch
a pinch of salt
1/4 teaspoon vanilla extract

Zest and juice the lemons. Reduce the zest with the juice by about 2/3rds. Temper with the egg yolks, sugar, salt, and cornstarch. Whisk on medium-high heat for about 3 minutes, or until thickened. Take off heat and whisk in your butter, then vanilla. Pass through a sieve and transfer to a piping bag. Refrigerate for at least 20 minutes, or until it is time to assemble. The curd cannot be too warm, or it will melt the mousse.

For the pistachio mousse:
1/4 cup shelled pistachios
a pinch of salt
1/4 cup water
2 tablespoons granulated sugar
1 1/2 teaspoons gelatin powder + 2 tablespoons water
1/4 cup heavy cream, whipped stiff
1/4 teaspoon vanilla extract

Puree water with pistachios, sugar, and gelatin. Pass through a sieve and reduce on low heat by half. Pour onto a sheet tray and refrigerate until room temperature. Fold in your whipped cream and vanilla and transfer to a piping bag. Refrigerate for at least 1 hour before using.

For the tempered chocolate disks:
1/4 cup white chocolate chips
1/4 teaspoon spirulina powder
a pinch of salt
3 tablespoons crushed pistachios

Temper white chocolate over a double boiler with salt and spirulina(melt 3 tablespoons first, and then stir in the last tablespoon off heat). Pour onto acetate and spread with an offset spatula to be no thicker than a fingernail. Sprinkle on your pistachios and refrigerate for 2 minutes. Cut out 1 to 2 inch circles and continue to refrigerate for another 5 minutes. Remove from acetate carefully.

To garnish:
Toasted pistachios

Use a microplane to file down any coarse or uneven edges on the tart. Pipe the curd into the bottom first, filling to the edges, and then smooth out with an offset spatula. Pipe on your mousse, then garnish with the tempered chocolate disks, lemon gelee, and pistachios to finish.