Preheat oven to 350°F (175°C).

Line a 9x13-inch baking dish with foil.

In a shallow dish, combine breadcrumbs, parmesan cheese, parsley, and crushed French-fried onions.

Melt butter in a saucepan over medium-high heat.

Add garlic and saute for about 1 minute, until fragrant.

Remove from heat.

Stir in Worcestershire sauce and dry mustard.

Dip each chicken breast in the butter mixture, then dredge in the breadcrumb mixture, ensuring it's well-coated.

Arrange the breaded chicken breasts in the prepared baking dish.

Pour any remaining butter mixture over the top of the chicken.

Bake in the preheated oven for 50-60 minutes, or until the chicken is cooked through and the internal temperature reaches 165°F (74°C).

Serve hot.