Cut the butter into 1/4" cubes and place back in the refrigerator for about 30 minutes.
Sift together the flour, salt, and baking powder and place it in the freezer for about 30 minutes.
Remove flour and butter from the refrigerator and have the ice water and apple cider vinegar ready for use.
Place the flour in a food processor and pulse for about 5 seconds.
Add the butter and pulse for about 10-15 seconds. The butter should resemble a coarse meal.
Drizzle in the water and apple cider vinegar and pulse for about 5-10 seconds, until the butter is the size of small peas.
Place the dough on a clean flat surface and using your hands bring the dough together by pressing it (DO NOT KNEAD!) into a disk.
If you would like to bake a lattice pie, divide the dough into 2/3 and 1/3 and wrap it in plastic wrap.
Let rest in the refrigerator for a minimum of 1 hour or overnight preferably.
When ready to bake, remove dough from the refrigerator. You can allow it to soften for 10 minutes at room temperature or bang it with a rolling pin.
Roll dough into 12"-14" circle (depending on the depth of your dish) and gently line rolled dough in the pie dish.
Create your design to crust edges and place back in the refrigerator while you make the streusel and filling.
Place the butter in a pan and over the stove medium heat. Let melt and cook for additional 7-10 minutes until the butter is brown and has a nutty aroma.
Remove from heat and let cool for 5-10 minutes.
As the butter cools, in a medium bowl mix the remaining ingredients.
Drizzle in the browned butter and use a fork or your fingers to crumble ingredients into your desired texture.
Peel, core and slice the pears into 1/4" slices.
Sprinkle lemon juice and toss for even distribution.
Mix the sugar and cornstarch together, sprinkle mix on pears and toss to distribute.
Preheat oven to 400F and place a rack at the lowest shelf of the oven. Line a large cookie sheet with parchment paper.
Remove the pie shell from the refrigerator.
Evenly line pear filling in pie shell and sprinkle with streusel. Brush crust edges with beaten egg.
Place ready to bake pie in the lined cookie sheet and bake for 10 minutes.
Reduce heat to 350F and bake for additional 45-50 minutes or until crust is golden brown and/or you notice some bubbles coming out the streusel.
Remove from oven and allow to cool completely before slicing.