Preheat oven to 350ºF | 180º C OR follow the temperature suggested in the GF pie crust package instructions. Grease 12 muffin cups with olive oil or butter.
In a medium non-stick pan over medium high heat, add olive oil and tomatoes and sauté for 2 minutes.
Add in the leek leaves, shredded chicken or turkey, parsley, thyme, sal and pepper and stir mixture to combine.
Pour in the white wine or water, give it a good stir, place the lid and bring everything to a boil.
Reduce heat to minimum and let simmer for 10 minutes.
In the meantime, roll out the pie crusts onto a flat surface. Using a 4-inch bowl and a sharp knife or a large cookie cutter, cut out 8 circles of dough (four in each pie crust). Repeat the process with a smaller 2,5-inch glass or cookie cutter. You should now have 8 big circles of dough for the bottom crust and 8 small ones for the top crust.
Press each big dough circle into the bottom of a muffin tin cup, leaving a tiny rim of dough sticking out at the top. Repeat with remaining dough to fill 8 muffin cups and prick each base with a fork.
Fill cups with the chicken or turkey filling until nearly full. Cover with the small circles of dough. Then using your fingers, gently press the top crust onto the bottom crust until they stick together and no gaps remain.
Brush the tops of each pie with the whisked egg. Then bake 30 to 35 minutes, or until the crust is lightly golden and the filling begins to bubble. You can also follow the pie crust package instructions.
Remove from the oven and let cool for at least 15 minutes. Carefully loosen the edges of each pie with a knife and gently lift out from the muffin tin.
Serve immediately or cover and refrigerate.