In a medium size bowl, mix together water, brown sugar and yeast. Mix in the flour and cover with plastic wrap. Allow to sit on the counter overnight or for at least 12 hours.
In a large bowl add starter dough, water and mix. Slowly incorporate the flour and add in extra-virgin olive oil. Lightly flour hands and mix the dough until a ball forms.
Remove dough from the bowl and onto a floured surface. Knead dough for about 10 minutes until smooth. Lightly spray a large clean bowl with non stick cooking spray. Add dough to bowl and cover loosely with plastic wrap. Allow to rise on the counter.
Once dough has risen once, fold dough into itself. Repeat this process three times.
Filling and Assembly
In a medium sized sauce pan set to low heat, mix together the turkey, soup, peas and water. Allow to simmer for 20 minutes, stirring occasionally. Remove from heat and allow to cool.
Lightly dust a counter top or cutting board with corn meal. Separate dough mass into two equal sections. Flatten out each section and cut into four sections.
Place about 2-3 tbsp of filling in each pocket, 1 tsp butter (evenly) and top with shredded Swiss cheese.
Carefully fold the dough over and seal the sides. See the attached image.
Using a small sharp knife, score the top of each pocket 3 times. Brush the top of each pocket with egg wash. Add each pocket to parchment paper before placing in oven.
Bake on stone or upside down baking sheet in oven set to 450 degrees for 10 minutes. Reduce oven temperature to 375 and bake for an additional 15 minutes. Allow to cool for 10 minutes before serving. The insides will be HOT.