Combine flour, salt, sugar and rosemary in food processor or stand mixer. Mix or pulse until combined.
Add in cubes of butter, and pulse or mix on low speed until you have course pea-size crumbs, about 30 seconds.
Slowly add in water, a little at a time, and mix or pulse until the dough starts to clump together. (It should maintain its shape when you squeeze it in your hand)
Form dough into two even balls. Flatten into discs and wrap with plastic wrap.
Refrigerate dough for at least 2 hours or overnight.
Chicken Pot Pie
Place chicken in medium sauce pan and sprinkle with salt and pepper. Cover with water and bring to boil. Cover, and cook 15-20 minutes until chicken is fully cooked. Drain water and set aside.
Melt butter in a pan over medium heat. Add onions, carrots, celery and garlic. Sprinkle with a pinch of salt and pepper.
Cook, stirring frequently, until tender and onions are translucent, about 10 minutes.
Add in chicken, thyme, allspice, cinnamon, flour, pumpkin, broth, and milk and peas. Whisk to combine until no flour lumps remain.
Continue simmering, whisking occasionally, until thickened, about 10 minutes. Season with salt and pepper if necessary and set filling aside.
Preheat oven to 375.
Once pie dough has chilled, remove from refrigerator and place on a lightly floured surface.
Roll each disc into a 10-12" circle.
Lay one disc in a 9" pie plate. Top with chicken pot pie filling. Top with second pie dough layer.
Seal the pie dough by using your fingers or a fork to crimp the edges. Cut 3 small slits in the top of the pie to release the steam.
Using a pastry brush, brush the crust and top of the pie with the beaten egg.
Bake for 45-60 minutes until the crust is golden brown and the mixture is bubbly. Let sit for 10-20
Remove from oven and let cool 15-20 minutes before serving.
*You can also use a pastry cut to cut the butter into the flour for the pie dough.*If you have leftover roasted chicken you can certainly use that as well! I like to use both dark and white pieces (boneless breast and thighs) for my chicken pieces.*Leftovers can be stored for up to 5 days in the refrigerator*To make chicken pot dough ahead of time, follow as instructed up until the egg brushing. Cover and refrigerate. When ready to cook, brush with egg wash and place in oven.