For the Dough

• 2 cups all-purpose flour
• 1 teaspoon baking powder
• ½ teaspoon salt
• 1 teaspoon sugar
• 4 tablespoons lard or vegetable shortening
• 2 tablespoons butter
• 1 large whole egg
• 1 large egg yolk

For the Filling

• 2 tablespoons butter or olive oil
• ¼ cup finely chopped onion
• 2 tablespoons flour
• 1 cup milk
• 1¼ cups grated fontina or Swiss cheese
• 1 (10-ounce) package frozen spinach, thawed
• Salt and freshly ground black pepper to taste
• Freshly grated nutmeg to taste
• About ¼ cup flour for the work surface
• Lard or vegetable oil for deep-frying; or 1 egg, beaten together with 1 tablespoon water, if baking

Make the dough: In a large mixing bowl, thoroughly combine the flour, baking powder, salt, and sugar. With a pastry blender or two knives, cut the lard and butter into the flour mixture until it resembles coarse cornmeal. Make a well in the middle of the flour mixture. Place the whole egg and egg yolk in the well. Use an electric mixer or a fork and your hands to mix in the egg and enough cold water (about ½ cup) to make a soft, smooth, pliable dough. Place the dough in a bowl, cover, and refrigerate for at least 30 minutes.

While the dough is chilling, make the filling: In a large saucepan over medium heat, melt the butter. Add the onion and sauté until softened, 2 to 3 minutes. Stir in the flour and cook, stirring, for 1 minute. Whisk in the milk and ¾ cup of the cheese. Cook, stirring, until the sauce thickens. Squeeze any excess moisture out of the spinach, then stir the spinach into the sauce. Fold in the remaining cheese. Taste and season with salt, pepper, and nutmeg.

Lightly flour a work surface. Divide the dough into 6 to 8 balls. Return all but one ball to the refrigerator. Roll the ball into a circle about ⅛ inch thick. Put 3 to 4 tablespoons of the filling in the middle of the dough circle. Brush the edges of the circle lightly with water. Fold the dough over to make a half circle. Trim the edges with a pizza wheel to make a neat half-moon shape. Press down with the tines of a fork to seal the edge. Continue to make empanadas until all of the dough balls and filling are used.

To fry the empanadas: In a deep-fryer or a deep, heavy skillet, heat enough lard to cover the empanadas completely to 365 to 375°F. Working in small batches to maintain the lard temperature, lower the empanadas into the hot fat. Fry, turning once or twice, until the empanadas are golden brown, 4 to 6 minutes. Remove and drain on crumpled paper towels.

To bake the empanadas: Preheat the oven to 350°F. Place the empanadas on a baking sheet lined with baking parchment or aluminum foil. Brush the tops with the egg wash. Bake until golden brown, 20 to 30 minutes Serve the empanadas hot or at room temperature.