Preheat oven to 400°F and toss cubed potatoes and eggplant with olive oil, salt, and pepper.
Roast vegetables on a baking sheet for 25 minutes until golden.
Cook cubed chicken in a skillet until browned, then add diced green pepper.
Pour in tomato sauce and simmer a few minutes.
Layer roasted potatoes and eggplant in a greased baking dish.
Top with the chicken and tomato sauce mixture.
Pour white cream sauce evenly over the top.
Sprinkle with shredded mozzarella cheese.
Bake at 375°F for 20–25 minutes until cheese is golden and bubbly.
Rest 5 minutes, garnish with parsley, and serve.
Tip: Cut all vegetables the same size for even cooking.
Tip: Let the casserole rest before serving so it holds its shape.