Put 2 1/2 cups flour, 8 tbsp. butter, lard, and half of the salt into a large bowl. Using your fingers, blend together until mixture resembles a coarse meal. Sprinkle 10 tbsp. ice-cold water over the mixture; stir gently with a fork until dough comes together. Halve dough; from it into 2 thick discs (my original notes to them called them "chubby" discs), each about 5" wide. Wrap disks separately in plastic wrap; refrigerate for 1 hour.

Unwrap 1 dough disk; transfer it to a well-floured surface. Whack it with a rolling pin several times to flatten it out; turn it over and repeat. Roll out dough to form an 11" circle; transfer it to a 9" deep-dish pie pan. (If dough tears and needs mending, dab a little water where it requires patching and "glue" on a piece of dough.) Cover with plastic wrap and refrigerate.

Arrange a baking sheet on lower rack of oven; heat to 425F. Put berries, 3/4 cup sugar, lemon juice, zest, nutmeg, remaining flour, and salt into a bowl. Using a wooden spoon, mash gently to make a textured filling; pour into chilled crust; dot with remaining butter; set aside.

Beat egg white and 1 tbsp. water together in a bowl; set aside. Roll out remaining dough disk into an 11" circle; cut into 3/4"-wide strips. Arrange strips over pie in a lattice pattern; trim excess dough and crimp edges of pie. Brush crust with egg mixture; sprinkle with remaining sugar. Bake on the middle rack of the oven until crust is just golden, about 15 minutes. Reduce heat to 350F; bake until golden brown and bubbling, about 30 minutes more. Let cool before serving.