First, prepare the dough. Combine all dough ingredients in a large mixing bowl and, using fingers, incorporate until dough begins to come together (it will still be slightly crumbly.) Using hands, form dough into a ball and then flatten slightly into a disc. Wrap in saran wrap and refrigerate for at least 30 minutes.
Next, prepare the cashew cream. Drain soaking water from the cashews and place in a high-powered blender. Add filtered water, nutritional yeast and salt and blend on high until a smooth cream forms. Set aside.
Now, time to prepare the filling. In a large saute pan, warm the olive oil over medium-high heat. Add the onion and saute for a few minutes, until they start to become translucent. Add the carrot, celery and garlic and saute for another 5-10 minutes, until vegetables begin to soften. Add the frozen peas and chicken breast, and then the cashew cream. Stir to combine and continue to cook until mixture is warmed through. Turn heat down to low and move on to prepping the dough.
Preheat the oven to 400 degrees Fahrenheit. Spray a large baking pan with nonstick cooking spray, or line it with parchment paper. Set aside.
Remove the dough from the refrigerator. You may need to let it warm up to room temperature a bit before you can roll it out. Once the dough is soft, roll it out to about ½ inch thickness. Using a large circle cookie cutter (I actually used a large ramekin since I didn’t have a large enough cookie cutter,) cut the dough into circles that are about 7-8 inches in diameter.
Scoop about two tablespoons of filling onto one half of each of the circles, and then fold the other half over top. Use your fingers to pinch the dough up around the edge and seal. Place pockets on the prepared baking sheet.
In a small bowl, whisk the egg to make the egg wash. Brush the wash over each of the pockets, then cut a small slit in the top of each to allow the filling to vent during cooking.
Place in preheated oven and bake for 25-30 minutes, or until the pockets are a nice golden-brown color. Serve warm.