In a large bowl, whisk together flour, sugar, and salt.
1 ½ tbsp granulated sugar, 3 ¼ c. unbleached all-purpose flour (RECOMMEND WEIGHING), ½ tsp salt
Cube cold butter and add to flour mixture. Toss to coat, keeping cubes separate. Flatten butter pieces between fingers, then use a pastry blender or your fingers to break into small, pea-sized pieces.
1 ½ c. salted butter
Place egg yolk in a measuring cup and add milk to reach a scant ¾ cup. Add yolk-milk mixture to flour mixture. Mix lightly with a fork or spatula until dough begins to form.
1 large egg yolk, ⅔ c. milk
Form dough into a ball, divide into two portions (one slightly larger for bottom crust, ~55% vs. 45%), wrap in plastic wrap, and refrigerate for at least 30 minutes.
Make the Filling:
In a large bowl, combine sugar, cinnamon, and tapioca pearls.
1 ¼ c. granulated sugar, 1 ½ tsp ground cinnamon, 3 tbsp quick-cooking tapioca pearls
Peel, core, and thinly slice apples (~1,200–1,400g whole, yielding 11–12 cups sliced, ~⅛-inch thick). Toss in sugar mixture to coat evenly. Set aside.
8-10 large tart apples
Assemble the Bars:
Preheat oven to 350°F (175°C).
On a well-floured pastry cloth or board, roll larger dough portion into an 11x16-inch rectangle. Transfer to an ungreased 10x15-inch jelly roll pan, pressing gently to fit with a ½-inch overhang.
Spread apple filling evenly over the bottom crust.
Roll second dough portion into a 10x15-inch rectangle. Place over filling, tuck edges under bottom crust’s overhang, and pinch to seal.
Whisk egg white with 1 tbsp water. Brush evenly over top crust.
1 egg white (reserved from crust), 1 tbsp water
Using a sharp knife or lame, make 10–12 small slashes (about 1 ½-inch long) across the top crust to allow steam to escape.
Bake the Bars:
Bake at 350°F for 60–70 minutes, until crust is golden brown and apples are fork-tender. Check at 60 minutes; baking time varies with apple slice thickness.
Cool and Drizzle:
Cool bars completely on a wire rack (at least 1 hour).
Whisk confectioners’ sugar, vanilla, salt, and 1–2 tbsp milk until smooth and spoonable. Drizzle over cooled bars with a spoon or piping bag. Let set before cutting into 16–20 bars.
¾ c. confectioner's sugar, 1 tsp vanilla extract, 1-2 tbsp milk, ⅛ tsp salt
Video
Notes
Crust Texture: The dough is wetter than a typical pie crust for tenderness. Use a well-floured pastry cloth to manage stickiness.
Apple Tips: Use tart apples like Granny Smith. Slice thinly (~⅛-inch) for even baking. Adjust bake time (60–70 min) based on thickness.
Thickener Options: Choose one thickener for the apple filling to achieve the desired texture. For 11–12 cups apples:
Quick-Cooking Tapioca Pearls (3 tbsp, 23g): Preferred for a smooth, glossy filling. Let the filling sit for 10 minutes after mixing to soften pearls.
All-Purpose Flour (⅓ cup + 1 tbsp, 45g): Creates a slightly cloudier, softer filling. Mix thoroughly with sugar and cinnamon.
Cornstarch (2 tbsp, 16g): Yields a clear, firm filling. Dissolve in a small amount of cold water before mixing to avoid clumping.
Crushed Cereal (1 ¼ cups, 50g, e.g., Corn Flakes or Rice Krispies): Adds a subtle texture, as used in Mom’s original recipe. Crush finely for best results.
Drizzle: Apply after cooling to keep the top crust crisp. For a thicker drizzle, start with 1 tbsp milk and adjust.