If using raw chicken, place it in a pot of boiling water and cook for about 15-20 minutes until fully tender. Ensure the chicken is no longer pink, then shred or dice it into bite-sized pieces.

In a large skillet, heat 2 tablespoons of butter over medium heat. Add the finely chopped onion and minced garlic, cooking for about 3-4 minutes until they become fragrant and the onions are translucent.

Slowly pour in 1 cup of heavy cream while stirring continuously to combine with the sautéed onion and garlic. Gradually whisk in 1 cup of grated Parmesan cheese, stirring constantly for about 3-5 minutes until the sauce thickens and becomes creamy.

Gently fold in the shredded chicken along with any optional chopped spinach or roasted red peppers. Stir until all the ingredients are well-coated, allowing the mixture to simmer for an additional 2-3 minutes.

Take 4 toasted sandwich buns and generously spoon the creamy chicken mixture onto the bottom half of each bun. If desired, sprinkle with shredded mozzarella.

For a delightful twist, consider serving the chicken Alfredo mixture over cooked pasta rather than in buns.