Sift four, 1/2 cup sugar and salt into a large bowl. Cut in butter until mixture resembles coarse breadcrumbs. Fold in egg yolks (mixture will be crumbly). Remove 1/4 of mixture, and set aside. Press remainder onto bottom and sides of a 20cm pie dish
In a large bowl, combine apples, brown sugar, 1 tablespoon flour, cinnamon and nutmeg. Place apples into the base, and sprinkle reserved crumb mixture evenly over top.
Bake the pie in preheated oven for 15 minutes. Reduce heat to 180 degrees C and continue baking 20 minutes, or until top is golden brown and filling is bubbling.