Preheat the oven to 375 degrees F. 

Add the oil to a large (oven-safe) skillet and set to medium heat. Add the onions and parsley and cook, stirring frequently for 3-4 minute or until the onions are tender. Add the flour and give it a few good stirs then whisk in the chicken broth and the milk. Reduce heat to a simmer and whisk occasionally until sauce thickens, about 10 minutes. Stir in the cauliflower and carrots and cook for about 5 more minutes or until tender. 

Turn off heat and stir in shredded chicken, salt and pepper. Taste and add more seasonings to your preference. 

Unfold puff pastry and cut off 1/4 of the dough. (You can use the whole sheet if you wish, I just decided to cut the fat down and 3/4 felt like plenty anyway!) Gently roll out on a floured surface. Roll out to an oval size that is slightly bigger/the same size than your skillet. Carefully pick the pastry up and place it over top of the skillet. Tuck the sides under the skillet to secure it, but it doesn’t have to fit perfectly/cover completely. 

Brush with the egg wash. Use a knife to make 2-3 slits on the top (so it looks pretty!)

Bake for 40-45 minutes or until the pastry is golden brown. Let cool for 10 minutes, sprinkle with fresh herbs and serve!