To begin, prepare the filling. Heat 2 tbsp of olive oil in a pan.
Add in a bay leaf. Add in the chopped garlic and saute until it begins to change color.
Add in the chopped onions. Saute until the onions are translucent.
Next, add the vegetables. Saute for a few minutes.
Add in the chicken mince and cook until the liquid dries up a bit.
Now add in the chicken stock and cook until the chicken mince is done.
Add in Worcestershire sauce, tomato puree, and tomato sauce. Mix well. Cover with a lid and cook until the sauce dries up a bit.
Finally, add in black pepper powder, rosemary, and thyme. Mix well. Make sure it is not too dry because it would bake in the oven.
Check the salt and add more if required. Remove to a bowl and keep aside.
For the topping, take boiled and mashed potatoes in a large bowl. Add in salt, butter, and an egg yolk. Mix well and keep aside.
To assemble the pie, in an oven-proof dish, spread out the filling in an even layer. Top it with the mashed potatoes and smoothen them out. With a fork, create a design of your choice.
In a pre-heated oven, bake it at 220°C for 20 minutes or until the potatoes start to color.
The Chicken Shepherd's Pie is ready to serve.