Sweet potato-filled empanadas are a comforting, naturally sweet Mexican pastry. This vegetarian, family-friendly treat is a warm, flaky, traditional confection with earthy sweetness.
Preheat the oven to 375°F. Line a baking sheet with parchment paper for later use.
Boil the sweet potatoes (unpeeled) in simmering water over medium heat for about 30 minutes, or until fork-tender. Cool slightly, peel, and mash them until smooth.
In a bowl, mix the mashed sweet potatoes, granulated sugar, ground cinnamon, salt, and vanilla extract until well combined. Set the filling aside.
In a large bowl, cut the cold unsalted butter into the flour until the mixture resembles coarse crumbs. Add 1 egg and milk, mixing gently until the dough comes together; avoid overworking for flakiness.
Divide the dough into 8 balls. Roll each into a thin circle. Place about 2 tablespoons of the sweet potato filling on one half, leaving edges clean.
Fold the dough over the filling to make a half-moon shape. Seal the edges by pressing firmly with a fork. Brush each empanada with beaten egg for a glossy finish.
Place the empanadas on the prepared baking sheet. Bake for 25–30 minutes, or until golden brown and flaky. Cool slightly before serving.