Preheat the oven to 350 degrees F.
To make bread crumbs: Trim the crust off the bread and discard, tear bread into pieces. Spread bread out on a microwave-safe plate, and microwave on HIGH for 1 minute to dry out the bread. (Alternately, spread the bread out on a baking sheet and dry in a preheated 300 degree F oven for 22 to 25 minutes.) Pulse the dried bread or crumbs in a food processor with the thyme, lemon zest, 3/4 teaspoon salt, and pepper.
With the flat side of a cook's knife or the smooth side of a meat-pounder, pound each breast to equal thickness. Put the flour, eggs, and the bread crumbs each separately in 3 shallow dishes. Pat the chicken dry and season both sides with salt and pepper. Dip each breast into the flour, then shake off the excess. Next, run the breast through the egg to coat it lightly and hold the chicken over the liquid to let any excess fall back into the bowl. Finally, lay the chicken in the bread crumbs, turn it over and press it into the breading to coat. Lay on a piece of waxed paper.
Heat a large skillet (12 inches in diameter) over medium heat. Add the oil. Lay 2 chicken breasts smooth-side down in the pan. Cook the chicken without turning until beginning to brown, about 2 minutes. Turn the chicken and cook until equally brown on the other side, about 2 minutes more. Repeat with the remaining 2 breasts. Transfer chicken to a paper towel lined plate to drain. Place all 4 breasts on a rack over a baking pan and bake until firm to the touch, about 6 to 8 minutes. Remove from the oven and serve immediately with lemon wedges.
Serving suggestion: Lemon wedges, thyme sprigs for garnish .