Peel and slice 6 Granny Smith apples. Melt 2 tablespoons of butter in a skillet over medium heat. Add the apples, 1/3 cup sugar, and spices. Cook for 8-10 minutes until the apples are slightly softened. Cool the filling thoroughly.

Combine 1 ½ cups of flour and ½ teaspoon salt in a food processor. Add 1 cup cold, diced unsalted butter until it resembles coarse crumbs. Gradually mix in 4-6 tablespoons of ice water. Shape into a disc, wrap in plastic, and refrigerate for at least 1 hour.

Melt 4 tablespoons of butter in a saucepan over medium heat. Stir in 1 cup brown sugar and slowly add ½ cup heavy cream. Bring to a gentle boil for 2 minutes, stirring constantly, then remove from heat to cool slightly.

Roll out half of the chilled crust on a floured surface and fit into a pie plate. Layer the cooled apple filling and drizzle toffee sauce on top. Roll out remaining dough to create a lattice or cover the pie. Seal edges tightly.

Preheat oven to 350°F (175°C). Brush crust with egg wash. Bake for 50-60 minutes until filling bubbles and crust is golden-brown.

Whisk together 3 egg yolks, 1/3 cup sugar, and 2 tablespoons cornstarch in a bowl. Heat 2 cups milk until just simmering, then whisk into the egg mixture. Return to saucepan and cook over low heat for 5-7 minutes until thickened. Strain the custard.

Once the pie has cooled for at least 10 minutes, slice and serve with custard drizzled over each slice.