Apple bar-shaped shortbread pie

Ingredients:

Shortcrust pastry

• 450 g unsalted butter at room temperature
• 3/4 cup granulated sugar
• 0.5 cups light brown sugar, lightly packed
• 2 tsp vanilla extract
• 4 cups premium flour
• 1.5 tsp coarse salt
• 0.5 cup chopped walnuts
• 1 teaspoon ground cinnamon

Apple filling

• 700 g Granny Smith apples, peeled, quartered, cores removed and sliced ​​0.3 cm thick.
• 700 g Golden Delicious apples, peeled, quartered, cores removed and sliced ​​0.3 cm thick.
• 2 tablespoons freshly squeezed lemon juice
• 1/4 cup granulated sugar
• 1 teaspoon ground cinnamon
• 1/8 tsp ground nutmeg
• 4 tbsp (55 g) unsalted butter

Preparation:

1. Preheat oven to 190°C.
2. Shortcrust pastry
   
   Place the butter, granulated sugar, brown sugar and vanilla in the bowl of an electric mixer fitted with the paddle attachment and beat on medium speed for 2 minutes until light and creamy.
3. Sift together the flour and salt and, with a mixer on low speed, gradually add the flour to the butter-sugar mixture until smooth. Place two-thirds of the shortcrust pastry dough into a parchment-lined 22x32 cm baking pan, forming lumps. Lightly press them into the bottom and up the sides 1 cm with floured hands.
4. Refrigerate the shortcrust pastry for 20 minutes. Bake the pastry in the pan for 18–20 minutes, until golden brown. Let cool.
5. Streusel: Meanwhile, return the bowl with the remaining dough to the mixer, add the walnuts and cinnamon, and mix on low speed until fully incorporated. Set aside.
6. Reduce oven temperature to 175°C.
7. For the fillingIn a very large bowl, combine the apples with the lemon juice. Add the granulated sugar, cinnamon, and nutmeg and mix well. Melt the butter in a large saucepan (25 cm in diameter), add the apples, and simmer over medium-low heat, stirring frequently, for 12–15 minutes, until the apples are soft and the liquid has almost completely evaporated. Spread the apples evenly over the crust, leaving a 1/2-inch border.
8. For topping, pinch off medium-sized pieces of chilled streusel dough with your fingers and arrange them evenly over the apples (they won't be completely covered). Bake for 25–30 minutes, until the topping is golden brown. Let cool completely and cut into squares.