Add flour and salt to a bowl. Mix well. Add cold butter cubes. Rub with fingers until crumbly texture forms. Add cold water slowly. Mix until dough comes together. Wrap and chill for 20 minutes.

Take sliced apples in a bowl. Add blueberries. Mix sugar, brown sugar, cinnamon, lemon juice, and cornstarch. Toss everything gently. Let it rest for 10 minutes so flavors blend well.

Take the chilled dough out. Divide into two parts. Roll one part into a round sheet. Make it large enough for your pie dish. Place it gently into the dish.

Pour the fruit mixture into the crust. Spread it evenly. Make sure apples and blueberries are balanced. This helps in even baking and better taste in every bite.

Roll the second dough piece. Place it over the filling. Seal the edges by pressing gently. Cut small slits on top. This allows steam to escape while baking.

Brush the top with beaten egg. This gives a golden color. Place pie on a tray. Bake at 180°C for 40–45 minutes until golden and bubbly.

Remove the pie from oven. Let it cool for at least 20 minutes. This helps the filling set properly. Slice and serve warm for best taste.