- 1 cup (2 sticks) chilled unsalted butter, cut into pieces
- 3 cups all-purpose flour, plus more for surface
- 1/2 teaspoon kosher salt, plus more
- 1 1/4 cups shelled fresh peas (from about 1 1/4 pounds pods), divided
- 2 tablespoons olive oil
- Freshly ground black pepper
- 1/2 cup whole-milk ricotta
- 1 teaspoon fresh lemon juice
- 1 large egg
- 1 teaspoon white wine vinegar
- 2 ounces smoked ham, cut into 1/4″ pieces
- Pulse butter, 3 cups flour, and 1/2 teaspoon salt in a food processor until mixture resembles coarse meal with a few pea-size pieces of butter remaining. With motor running, stream in 1/2 cup ice water and process, adding more water by the tablespoonful if needed, until a shaggy dough comes together and starts to form a ball around the blade (a few dry spots are okay).
- Transfer mixture to a lightly floured surface and gently knead until dough comes together completely (don't overmix). Divide dough in half, flatten each piece into a 1/2″-thick square, and wrap in plastic. Chill until cold, at least 2 hours.
- Meanwhile, cook peas in a medium saucepan of boiling salted water until bright green, about 30 seconds. Drain and transfer to a bowl of ice water to cool. Drain and pat dry.
- Blend oil and 1 cup peas in a food processor until smooth; season pea purée with salt and pepper.
- Mix ricotta and lemon juice in a small bowl; season with salt. Whisk egg and vinegar in another small bowl.
- Preheat oven to 375°. Let dough sit at room temperature, about 5 minutes, to soften slightly, making it easier to roll. Working with 1 square at a time, roll out dough on a lightly floured surface to about a 13×11″ rectangle. Trim to 12×10″, then cut into eight 5×3″ rectangles. (A ruler in the kitchen is a useful thing, but if you're not that particular, eyeball it.)
- Arrange 8 rectangles on a parchmentlined rimmed baking sheet, spacing 2″ apart. Spread 1 tablespoon ricotta mixture over each, leaving a 1/2″ border, then spread a dollop of pea purée over ricotta. Top with ham and remaining whole peas.
- Brush borders with egg wash and top with remaining 8 rectangles of dough, pressing gently around edges to seal. Crimp with a fork. Brush tops of tarts with egg wash and make 3 slits in the center of each (for steam to escape). Sprinkle with salt and pepper and bake, rotating halfway through, until tarts are deep golden brown, 35-40 minutes. Transfer to a wire rack and let cool 15 minutes.
- Do ahead: Dough can be made 3 days ahead; keep chilled. Hand pies (without egg wash) can be formed 1 day ahead; cover and chill. Brush with egg wash just before baking.