Leek and Potato Tart with Pistachio Crust (French Galette de Poireaux et Pommes de Terre en Croûte de Pistache)

Adding ground pistachios creates a substantial dough that complements the leeks for these galettes.

Dough:
½ cup raw pistachios
2½ cups all-purpose flour, unbleached
1 tsp. sea salt
1 tsp. sugar
1 cup (2 sticks) butter, chilled, cut into pieces

Filling and Assembly:
1 Tbsp. extra-virgin olive oil
1 large leek, white and pale-green parts only, halved lengthwise, thinly sliced
4 oz fresh goat cheese
5 Tbsp. heavy cream
2 cloves garlic, finely chopped
sea salt
black pepper, freshly ground
all-purpose flour
4 Tbsp. dill, coarsely chopped, divided
2 large Yukon Gold potatoes, thinly sliced
1 large egg, beaten to blend

To Serve:
crushed pink peppercorns, optional
dill sprigs

Make the Dough:
Pulse pistachios in a food processor until coarsely ground. Add flour, salt, and sugar and pulse to combine. Add butter and pulse just until a coarse meal forms. With motor running, gradually stream in ½ cup ice water and process until dough comes together. Transfer dough to a work surface; form into a ball, then flatten into a disk. Wrap in plastic and chill at least 30 minutes.

Make-Ahead: Dough can be made 1 day ahead. Keep chilled.

Preheat oven to 400°F (200°C/180°C fan, Gas Mark 6).

Filling and Assembly:
Heat 1 Tbsp. oil in a small skillet over medium-low. Cook leek, stirring occasionally, until softened but without taking on any colour, about 5 minutes. Transfer to a plate.

Mix goat cheese, cream, and garlic in a medium bowl to combine; season with salt and black pepper.

Divide dough into 4 pieces. Roll out 1 piece of dough on a lightly floured surface to an 8" round; transfer to a parchment-lined baking sheet. Using an offset spatula, spread one-quarter of goat cheese mixture over dough, leaving a 1" border. Scatter 1 Tbsp. dill evenly over, then top with a thin layer of potato slices. Drizzle with oil; season with salt. Scatter one-quarter of leeks over potatoes. Fold edges of dough over filling, tucking and overlapping slightly as needed. Repeat with remaining dough, goat cheese mixture, chopped dill, potatoes, and leeks and more oil and salt to make 3 more galettes. Brush top of dough with egg.

Bake galettes until crusts are golden brown and potatoes are soft, 30-40 minutes. Drizzle with honey and top with dill sprigs. Sprinkle with pink peppercorns, if using; season with salt and black pepper.

Makes four 6" galettes.