Cook Ground Beef (1.5 pound) until brown, continue stirring and breaking the pieces into the same size with a wooden spoon.
Add Yukon Gold Potato (4). Cook over medium-high heat for 5-6 minutes.
Drain some of the fat from the pan. Add Onion (1), Water (2 cup), Tomato Paste (1/4 cup), Salt (1 teaspoon), Ground Black Pepper (3/4 teaspoon), Chili Powder (1 tablespoon), and Garlic Powder (2 teaspoon). Stir to combine.
Add Sour Cream (4 ounce), Tomato (1), and half of the Mozzarella Cheese (2 1/2 cup). Cook for 2 minutes, then bring to a boil.
Reduce heat to medium and cook for 5-10 more minutes, until potatoes are fork tender.
Turn off the heat and add Broccoli Florets (1 1/2 cup). Let rest for 15-20 minutes while you make your pie crust.
In a mixing bowl, add All-Purpose Flour (2 2/3 cup), Salt (1 teaspoon), and Vegetable Shortening (1 cup). Use a pastry cutter to bring the mixture together.
Add the Water (12 tablespoon) one tablespoon at a time, mixing as you go, until mixture comes together into a dough.
Preheat oven to 375 degrees F (190 degrees C).
Turn the dough out onto a floured surface and divide into two pieces, making one slightly larger for the bottom layer.
Roll the dough out by placing a rolling pin in the center and gently pushing out to the edges, until dough is 1/4-inch thick.
Transfer the dough into a cast-iron skillet.
Pour the filling in.
Top with remaining cheese.
Roll out the other piece of dough and place it over top. Seal the edges with a fork and trim excess dough.
Using a knife, poke a few vent holes in the top of the pot pie.
Bake for 45 minutes-1 hour, or until the top is golden-brown.