French Apple Turnovers (Chaussons Aux Pommes)

Peel, core, and cut apples into 1-inch pieces (about 4 cups). Place apples in medium saucepan; add 1/4 cup water, 3 tablespoons sugar, and lemon juice. Bring to boil, stirring occasionally until sugar dissolves. Cover; reduce heat to medium-low and simmer until apples are very tender, stirring frequently, about 12 minutes. Remove from heat. Gently mash apples with fork or potato masher until mixture is very soft but still chunky. Cool completely. DO AHEAD: Filling can be made 2 days ahead. Cover and refrigerate. Position 1 rack in top third and 1 rack in bottom third of oven and preheat to 400 °F. Line 2 baking sheets with parchment paper.