In a large pot, heat the pancetta over medium heat. Cook until the fat has rendered and it’s golden brown, 5-6 minutes.
Add the shallots and sauté until tender, 2-3 minutes. Stir in the garlic and sauté until fragrant, 1 minute more.
Add the kale in batches—adding handfuls and sautéing until it wilts. Once all the kale is added, season with salt, pepper, and red pepper flakes.
Add the wine to the pan and sauté until it evaporates, 6-8 minutes. Stir in the rosemary.
Add the heavy cream and bring to a simmer. Simmer until the mixture thickens slightly, 5-6 minutes more. Stir in the walnuts.
Preheat the oven to 375°F. Line a baking sheet with parchment paper and place a 9 inch springform pan on it.
Prepare the Hot Water Crust as directed by the recipe, then divide into two pieces—one about 2/3 of the dough (for the base and sides) and one about 1/3 of the dough (for the top).
Start with the larger piece for the base and sides. Remember, you have to work with the crust while it’s hot to keep it pliable. I like to roll it out as best I can between two sheets of plastic wrap to about 1/4 inch thick (a little thicker is OK, too).
Peel the top piece of plastic wrap off, then use the bottom piece to help you invert the dough into the springform pan. Don’t worry if it tears or small holes appear—you can patch it! Patch any holes, tears, or uncovered areas with more dough, and press well to ensure they’re sealed. (Alternatively, you can just press the crust in from the get go— just remember to work quickly!)
Pour the filling into the pan and spread into an even layer. Transfer the springform pan back to the parchment lined baking sheet.
Roll out the remaining dough between two sheets of plastic wrap to about 1/4 inch thick. Peel off the top piece of plastic wrap then use the bottom piece to help you invert the crust on top of the filling, then peel it away.
Pinch the two crusts together at the sides, and pinch off any excess. Crimp the edges as desired to make sure they’re sealed together.
Use the handle of a wooden spoon to make a vent in the center of the pie. Bake the pie until the crust is golden brown and steam is coming out of the vent, 40-45 minutes. Cool at least 15 minutes before unmolding, slicing, and serving.
I always carry three kinds of hot sauce in my purse. I have a soft spot for making people their favorite dessert, especially if it's pie. My first cookbook, The Fearless Baker, is out on October 24, 2017.