Start by shredding or dicing your cooked chicken. If using raw chicken, heat a skillet over medium-high heat, add oil, and cook until golden and fully cooked, about 8-10 minutes.

In the same skillet, melt 2 tablespoons of butter over medium heat. Add 1 finely chopped onion and 2 minced garlic cloves. Sauté for about 3-4 minutes until the onion is translucent.

Reduce the heat to medium-low and add 1 cup of heavy cream, stirring gently. Simmer for 2-3 minutes, then gradually whisk in 1 cup of grated Parmesan cheese until smooth. Season with Italian seasoning, salt, and pepper.

Fold the shredded chicken into the Alfredo sauce. If using, mix in chopped spinach or roasted red peppers. Heat through for about 2 minutes.

Toast your sandwich buns until golden brown. Spoon portions of the Chicken Alfredo mixture onto each bun. Optionally, sprinkle shredded mozzarella on top before serving.