Marinate the diced chicken with salt, pepper, chili powder, and onion salt, then let it sit for at least 15 minutes.
Preheat the oven to 180°C (356°F) and brush both bread halves with melted butter.
In a pan, melt 1 tablespoon of butter and sauté the marinated chicken until golden brown, then remove it from the pan and set aside.
In the same pan, pour in the heavy cream and stir in the Parmesan cheese.
Add the shredded cheese and mix until the sauce is smooth and creamy.
Spread the Alfredo sauce evenly over the bread halves, then distribute the cooked chicken on top.
Bake for 30 minutes until golden and crispy.