Cut the chicken breasts into ½ inch pieces, drizzle with olive oil and season. Cook over medium heat until golden brown.
Slice the Italian loaf in half. Combine melted butter, minced garlic, chopped parsley, and crushed red pepper flakes in a bowl.
Spread the garlic butter mixture on both halves of the loaf and toast in a preheated oven at 350°F for 5 to 10 minutes.
In the same pan, melt half a stick of butter, add minced garlic, then heavy cream and parmesan cheese. Simmer until thickened.
Spread half of the sauce over each toasted bread half, top with chicken pieces and mozzarella cheese, then add remaining sauce.
Bake at 350°F for another 5 minutes until melty and bubbly. Slice and serve warm.