1 cup Nash’s soft white flour
1 cup Nash’s hard red or triticale flour
1 teaspoon salt
1 1/2 sticks butter, frozen, then grated
1 tablespoon apple cider vinegar
1 cup ricotta cheese
3 tablespoons olive oil, divided
4 ounces mushrooms, thinly sliced
1 clove garlic or 1 garlic scape, finely chopped
1 large bunch rainbow chard, ribs and stems removed, leaves cut into bite-size pieces
Flour for parchment
1 large egg, beaten to blend
1 cup mixed fresh cilantro and basil
1 teaspoon finely grated lemon zest
1 teaspoon fresh lemon juice
Pulse flours and salt in a food processor to combine. Add butter and pulse until mixture resembles coarse meal with a few pea-size pieces of butter remaining.
Transfer mixture to a large bowl; drizzle with vinegar and 1/4 cup ice water. Mix with a fork, adding more ice water by the tablespoonful if needed, just until a shaggy dough comes together; lightly knead until no dry spots remain (do not overwork). Pat into a disk and wrap in plastic. Chill at least 2 hours. Dough can be made 2 days ahead, but keep it chilled.
Preheat oven to 400°F. Season ricotta with salt and pepper; set aside. Heat 1 tablespoon oil in a large skillet over medium-high heat. Add mushrooms; season with salt and pepper and cook, stirring occasionally, until golden brown and crisp, about 5 minutes. Transfer to a small bowl.
Heat 1 tablespoon oil in same skillet over medium heat. Cook garlic, stirring, until fragrant, about 30 seconds. Add half of chard, season with salt and pepper, and cook, tossing, until slightly wilted. Add remaining chard and cook, tossing occasionally, until completely wilted, about 4 minutes. Remove from heat; season with salt and pepper. Set aside.
Roll out dough on a lightly floured sheet of parchment to a 14″ round about 1/8″ thick. Transfer on parchment to a baking sheet. Spread three-fourths of ricotta over dough, leaving a 1 1/2″ border. Top with reserved chard, then mushrooms. Dollop remaining ricotta over vegetables. Bring edges of dough up and over filling, overlapping as needed, to create a 1 1/2″ border; brush with egg. Bake galette, rotating once, until crust is golden brown and cooked through, 35–40 minutes. Let cool slightly on baking sheet.
Toss herbs with lemon juice and remaining 1 tablespoon oil in a small bowl; season with pepper. Top galette with herbs, zest, and salt.