Prepare the Filling: Heat the olive oil in a pan. Sauté the onion and garlic until fragrant. Add the cooked chicken and cook until it turns golden brown. Add the tomato paste, then season with salt, black pepper, and chopped parsley. Stir well and set the mixture aside.

Make the Batter: In a blender, mix the skim milk, oil, butter, eggs, and mashed potatoes until smooth. Pour this mixture into a large bowl. Add the whole wheat flour, baking powder, and a pinch of salt. Mix until well combined.

Assemble the Pie: Pour half of the batter into a greased baking dish. Spread the chicken filling evenly over the batter using a spoon. Then, dot with the cream cheese and sprinkle the mozzarella cheese on top.

Add Top Layer and Bake: Cover the filling with the remaining batter. Bake the pie in a preheated oven at 200°C (400°F) for about 30 minutes, or until the top is golden brown and cooked through.