In a large Mixing Bowl, whisk together 2½ cups ⅓ cup harina de trigo, 1 tsp 1 tsp sal kosher más al gusto, and 1 tsp 1 tsp azúcar granulada. Add the cold 4 tbsp mantequilla sin sal cubes and use your fingertips to work the 4 tbsp mantequilla sin sal into the ⅓ cup harina de trigo until the mixture resembles coarse crumbs with some pea-sized pieces remaining — this creates flakiness.

Drizzle in ice water one tablespoon at a time, tossing gently with a fork after each addition, until the dough just comes together and holds when pinched. You may not need all the ½ cup agua helada añadida 1 cucharada a la vez. Do not overwork the dough.

Divide the dough into two equal discs, wrap each tightly in Plastic Wrap, and refrigerate for at least 30 minutes (or up to 2 days). Cold dough is much easier to roll and produces a flakier crust.

Melt 4 tablespoons of 4 tbsp mantequilla sin sal in a large Skillet over medium-high heat. Season the 1 ½ lb pechugas de pollo sin hueso y sin piel cortadas en cubos de 3/4 pulgada cubes with a pinch of 1 tsp sal kosher más al gusto and 1 tsp sal kosher más al gusto, then add them to the Skillet in a single layer. Cook for 4–5 minutes, stirring occasionally, until lightly golden and just cooked through. Transfer the 1 ½ lb pechugas de pollo sin hueso y sin piel cortadas en cubos de 3/4 pulgada to a plate and set aside.

In the same Skillet over medium heat, add the diced 1 cebolla amarilla picada en cubos, 3 tallos apio en rodajas, and 3 zanahorias medianas peladas y picadas en cubos. Sauté for 6–7 minutes, stirring occasionally, until the vegetables are softened. Add the 3 dientes ajo picados finamente and 1 tsp hojas de tomillo fresco and cook for 1 more minute until fragrant.

Sprinkle the ⅓ cup harina de trigo over the vegetables and stir well to coat everything evenly. Cook for 1–2 minutes to eliminate the raw ⅓ cup harina de trigo taste.

Slowly pour in the 2 cups caldo de pollo de sodio bajo preferido while whisking constantly to prevent lumps. Then add the ¾ cup leche entera and ¼ cup crema pesada. Bring the mixture to a gentle simmer over medium heat, stirring frequently, and cook for 4–5 minutes until the sauce thickens enough to coat the back of a spoon.

Remove the Skillet from the heat. Stir in the cooked 1 ½ lb pechugas de pollo sin hueso y sin piel cortadas en cubos de 3/4 pulgada and 1 cup guisantes congelados no es necesario descongelar. Taste and adjust seasoning with 1 tsp sal kosher más al gusto and 1 tsp sal kosher más al gusto as needed. Let the filling cool slightly while you roll out the crust — a slightly cooled filling prevents the bottom crust from getting soggy.

Preheat your Oven to 425°F. On a lightly floured surface, roll one disc of dough into a 12-inch circle. Carefully transfer it to a 9-inch Pie Dish, pressing it gently into the bottom and sides. Let any excess hang over the edge.

Pour the filling into the prepared crust, spreading it into an even layer. Roll out the second disc of dough into another 12-inch circle and lay it over the filling. Trim any excess dough to about a 1-inch overhang, then fold the edges under and crimp them together firmly with your fingers or a fork to seal.

In a small Mixing Bowl, whisk together the 1 huevo batido and 1 tablespoon of ¾ cup leche entera to make the egg wash. Brush the egg wash evenly over the top crust. Cut 4–5 small slits in the center of the top crust to allow steam to escape during baking.

Place the Pie Dish on a Baking Sheet to catch any drips. Bake at 425°F for 30–35 minutes, until the crust is deep golden brown and the filling is bubbling through the vents. If the edges begin to brown too quickly, cover them loosely with strips of Aluminum Foil after the first 20 minutes.

Remove from the Oven and let the pot pie rest for 10–15 minutes before slicing. This allows the filling to set slightly so it holds together when served.