Preparation

Make the dough.

• In a mixing bowl, combine the 10 oz. flour, the 1 tsp. sugar, and the salt. Cut the butter into the flour mixture, using a pastry cutter or your fingers, until the butter bits are pea-size. (You can also use a food processor or a stand mixer, just be sure not to overmix the dough.) Add the water all at once and mix until the dough just comes together. Divide the dough and shape it into two disks.
• Cut each disk into quarters. With lightly floured hands, shape each quarter into a flat oval about 3 inches long and 2 inches wide. Cover the ovals with plastic wrap and refrigerate for at least half an hour.

Assemble and bake the turnovers:

• Line two baking sheets with kitchen parchment. Heat the oven to 400°F. Flour a smooth work surface well. With a rolling pin, roll each piece of dough into a larger oval, approximately 10 inches long and 6 inches wide. The dough should be almost paper-thin. Brush off any excess flour.
• Spoon 1 tsp. flour and 1 tsp. sugar on one half of each oval. Reassemble half an apple on each pile of flour and sugar. Sprinkle 2 tsp. sugar and a pinch of cinnamon over the apple.
  

• Fold the other half of the oval over the apples so that it falls just shy of the edge of the bottom half. Gently mold the dough around the apple to eliminate any trapped air. Fold the edge of the bottom half up over the edge of the top half and press to seal. Flute the edge as you would a pie. Brush the top of the turnovers with the melted butter and sprinkle with additional sugar. Bake until golden brown, 45 to 50 minutes. Use a spatula to move the turnovers from the baking sheet to a cooling rack. These are best served warm but are also good at room temperature.