01 -
Preheat oven to 400°F.
02 -
In a large skillet or Dutch oven, melt butter over medium heat and add diced onions. Cook until translucent. Add sliced mushrooms, season with salt and black pepper, and cook until mushrooms release liquid and begin to brown, about 10 minutes.
03 -
Sprinkle flour over the mixture and add chicken broth. Stir well to eliminate lumps and create a thick gravy.
04 -
Stir in sugar snap peas and mixed frozen vegetables until evenly incorporated.
05 -
Season the mixture with Kosher salt and black pepper to taste, stir in heavy cream, and adjust seasoning if necessary.
06 -
Add shredded rotisserie chicken and stir to combine. Mix in fresh thyme leaves and transfer the filling to a casserole dish.
07 -
Beat the egg with water to create an egg wash and set aside.
08 -
Unwrap and lay the pie dough flat. Slice into 3/4-inch strips and weave into a lattice design on parchment paper.
09 -
Carefully place the lattice design over the casserole by flipping the parchment paper confidently. Remove the parchment and adjust the lattice as needed, letting the edges drape over the sides.
10 -
Place the casserole on a rimmed baking tray. Bake for 30 minutes, or until the filling bubbles and the crust turns golden brown. Cover with foil if crust browns too quickly.
11 -
Remove from oven, top with additional fresh thyme, and let rest for 10 minutes before serving.