Combine flour, sugar, and salt in a food processor and pulse.

Add shortening and process.

Sprinkle in butter and pulse until crumbly.

Transfer to a bowl.

Work in egg mixture, one-third at a time.

Knead the dough into a ball and flatten into a disk.

Wrap in plastic and refrigerate for at least 1 hour.

Heat oil in a skillet over medium heat.

Add onion and garlic and cook until translucent.

Add beef and cook until browned.

Add sweet potato, water, soy sauce, salt, and pepper.

Stir, lower heat, and cover.

Cook until the potato is nearly tender.

Uncover, add raisins, and cook until the potato is tender and there is very little liquid left.

Mash half of the potato and transfer to a bowl to cool.

Let the dough sit at room temperature until malleable.

Preheat oven to 375F.

Line baking sheets with parchment paper.

Lightly beat the egg white.

Unwrap the dough and roll it into a 12-inch log.

Cut the log into 12 pieces.

Roll each piece of dough into a circle.

Position filling off-center on the wrapper.

Brush egg white on half of the rim and close.

Press with fingers to seal the rim.

Place on the baking sheet.

Lightly beat the egg yolk and brush it on the turnovers.

Bake for 20 to 22 minutes, until golden brown.

Cool before eating.