Step 1

In the bowl of a food processor, pulse together 2 cups of the flour, the cornmeal, 1/2 teaspoon of the kosher salt, and 1/4 teaspoon of the pepper until combined.

Step 2

Add 1 cup of the cold butter and pulse together until the mixture is crumbly.

Step 3

With the processor running, add the buttermilk in a slow, steady stream just until the dough comes together.

Step 4

Using the extra flour, lightly dust a work surface. Turn the dough out onto the floured work surface.

Step 5

Divide the dough in half.

Step 6

Shape each portion into a disk and wrap them individually in plastic wrap.

Step 7

Refrigerate the dough disks for at least 1 hour.

Step 8

Using the extra flour, lightly dust another work surface. Roll one portion of the dough into a 10x14-inch rectangle, reserving the other dough disk for another use.

Step 9

Preheat the oven to 375 degrees F.

Step 10

Spray a 9x13-inch baking dish with cooking spray.

Step 11

In a large Dutch oven, add the potatoes and enough of the extra water to cover them by about 1 inch.

Step 12

Bring the potatoes to a boil over medium-high heat.

Step 13

Reduce the heat to low and simmer until the potatoes are tender, about 15 minutes, adding the carrots during the last 5 minutes of cooking.

Step 14

Drain the potatoes and the carrots well and set them aside.

Step 15

In the Dutch oven, heat 2 tablespoons of the oil over medium heat.

Step 16

Add the onions and cook, stirring occasionally, until golden-brown, about 15 minutes.

Step 17

Transfer the onions from the pot.

Step 18

In the Dutch oven add 2 tablespoons of the oil over medium-high heat.

Step 19

Season the steak with 1 teaspoon of the salt and the remaining pepper.

Step 20

Add 1/2 of the steak to the pot and cook until browned, about 2-3 minutes per side.

Step 21

Transfer the steak from the pot.

Step 22

Repeat the cooking process with the remaining oil and the remaining steak.

Step 23

Melt the remaining butter in the Dutch oven over medium heat.

Step 24

Add the remaining 1/2 cup of the flour and cook, stirring constantly, until golden, about 1 minute.

Step 25

Gradually stir in the beef broth and cook, stirring constantly, until thickened, about 10 minutes.

Step 26

Stir in the cooked potato mixture, the onions, the steak, and 1 tablespoon of the rosemary and cook the mixture until it just comes to a simmer.

Step 27

Pour the steak-potato mixture in the prepared pan.

Step 28

Top the pan with the prepared cornmeal-buttermilk pie dough.

Step 29

Cut decorative slits into the dough to let the steam escape.

Step 30

In a small bowl, whisk the egg and the remaining 1 tablespoon of the water together.

Step 31

Brush the egg wash over the dough.

Step 32

Sprinkle the dough with the remaining salt.

Step 33

Bake until the crust is golden-brown and the filling is bubbly, about 20-25 minutes.

Step 34

Let the bake stand for 10 minutes.

Step 35

Garnish with the extra rosemary and serve.