4boneless, skinless chicken breast halves (1-1/2 to 1-3/4 lbs)
For the herb-butter:
6tablespoonsunsalted butter, softened
1small shallot, very finely chopped
1tablespoonfresh chives, finely chopped
1tablespoonfresh parsley, finely chopped
1tablespoonfresh tarragon, finely chopped
1/4teaspoonfreshly ground black pepper
Start by preparing the herb butter. Place the softened butter in a small bowl. Add the shallot, chives, parsley, tarragon, salt and freshly ground black pepper.
Combine thoroughly, then transfer the mixture to a sheet of wax paper. Shape the butter into a rectangle about 2 inches wide by 4 inches long and smooth with the spatula to a uniform thickness. Wrap tightly and place in the freezer for about 20 minutes.
While the butter chills, gently pound the chicken breasts between 2 sheets of plastic wrap to a thickness of about 1/4 inch. Season on both sides with salt and pepper and set aside.
Remove the butter from the freezer and cut into four 2 x 1-inch pieces. Place one piece of butter in the center of each chicken breast, then roll as tightly as possible, tucking in the sides of the breast as best you can. Place the rolls seam side down on a plate and refrigerate for 30 minutes.
Preheat the oven to 400°F and coat a 9 x 9-inch baking dish with nonstick spray.
Whisk the egg and milk together in a shallow dish and spread the breadcrumbs on a dinner plate.
Carefully coat each piece of chicken with the egg mixture, then roll in the crumbs, patting gently to help them adhere.
Cover the bottom of a large nonstick pan with vegetable oil and heat over medium-high heat. Add 2 pieces of chicken and turning carefully with tongs, cook until light golden on all sides, about 3 minutes total. Transfer to the prepared baking dish and repeat with the remaining chicken.
Bake for 15 to 18 minutes or until the chicken is no longer pink in the middle. Allow to rest for 5 minutes before slicing.