In a small non-stick saute pan, heat olive oil over a medium-high heat. Season chicken breast with salt and pepper. Brown on both sides, and then pop into the oven to finish cooking, about 10-15 minutes. Let cool, chop and reserve juices that accumulate.
In a large skillet, heat 1 tablespoon butter over a medium heat. Add sweet potatoes. Sweat for 3-4 minutes.
Add remaining butter, onion, carrots and salt. Sweat 1-2 minutes and then cover completely with a lid and let steam for another 1-2 minutes until carrots and sweet potatoes are softened.
Stir in flour until completely absorbed, cook one minute.
Stir in stock and milk. Bring to a boil and then reduce to a simmer until thickened.
Remove from heat and add chicken, peas and sherry.
Season with salt and pepper if necessary.
Divide filling between two oven safe bowls or crocks.
Cut the phyllo into squares big enough to fold over bowls. (You should get 14 squares out of the dough) Spray each layer of dough with coconut oil spray, then overlap then next layer, staggering it diagonal. Repeat until you have seven layers. Place over each bowl, folding the sides down. Cut a little x in the middle to let steam escape.
Place on a baking sheet, bake until phyllo is golden brown and filling is hot. If the dough browns too quickly, just cover with foil until the filling is hot.