On a clean cutting board, spread out 1 sheet of wax paper or plastic wrap. Place 1 chicken breast on the wax paper and top with a second sheet.
Using a meat mallet or rolling pin, pound the chicken breast until it is evenly flattened to about 1/4 inch thick. Repeat with remaining chicken breast halves. (You may need new sheets of wax paper or plastic wrap for each breast.)
Spread the chicken breasts out and sprinkle 1/8 teaspoon of salt and pepper on each. Layer 2 slices of ham and 2 slices of Swiss cheese on each. Fold the chicken breasts in half and press to flatten and seal the edges, making sure the ham and cheese are tucked securely inside each chicken breast.
Place the flour in a medium mixing bowl. In a second medium mixing bowl, whisk together the eggs and milk. Mix together the bread crumbs and Essence in a third medium mixing bowl.
Carefully dip each folded chicken breast one at a time into the flour mixture, dusting off the excess flour. Then dip the chicken into the egg mixture, then coat well with the bread crumb mixture, patting to make sure the bread crumbs stick well to the chicken. Place the breaded chicken on a large plate, cover, and refrigerate for 20 minutes.
In a large nonstick skillet, heat the olive oil over medium heat.
When the oil gets very hot, but not smoking, carefully place the chicken breasts into the skillet with 1 tablespoon of the butter, being careful not to overcrowd the pan. Cook until golden brown, 4 to 5 minutes. Using a spatula or tongs, carefully turn the chicken breasts and add the remaining tablespoon of butter. Cook for an additional 4 to 5 minutes, until the chicken is browned and cooked through.
Remove the chicken from the pan and place on a paper towelñlined plate to drain.
Serve immediately, and be careful when cutting into the chicken, as the hot cheese will ooze out.
Yield: 4 servings