Here's what you need for about 4-6 servings:
1 package of thin-sliced boneless/skinless chicken breasts
1 egg, lightly beaten
For the sauce:
1 large can of crushed tomatoes
1 small onion, diced
garlic to taste
Fresh or dried basil
sliced or shredded mozzarella cheese
(Sorry not to give you exact amounts here, but so much of this can/should be done to taste.)
After you rinse and dry the cutlets, dip them in the egg and then dredge in breadcrumbs. Place the cutlets on a cookie sheet or jelly roll pan (if your pan is not non-stick, you may want to spray a little Pam on there, or use a sheet of parchment paper to prevent sticking).
Now, here's where we can enter a debate about frying or baking. Frying is outrageously delicious, no doubt about it. But baking is perfectly fine and usually my choice for a couple reasons: it's healthier and easier. I typically bake the cutlets in a 350 degree oven for about 20 minutes. Toward the end of the baking time, I drizzle the cutlets with olive oil and switch the oven to broil for a minute or two.
While the cutlets are cooking, make the sauce:
Drizzle a bit of olive oil in a heavy pan and saute the onion. When the onion is translucent and soft, add the can of crushed tomatoes and season with basil, garlic, salt and pepper. (If you like oregano, toss some of that in there too.)
Heat through, and then let the sauce simmer while the cutlets cook. This is an easy sauce, one that cooks quickly (and certainly don't be afraid to substitute your own recipe for marinara sauce—you can use fresh tomatoes or open a jar, you'll get a good result either way.)
Cover the bottom of a casserole dish with a little sauce. Layer the chicken on top. You can make a single layer or overlap, depending on the size of the pan and the number of cutlets you have. Top with more sauce (and again, use as much or as little as you like. The beauty of this dish is that there is no right or wrong way to do it. Lottsa sauce? Great. Easy on the sauce? Okay too.)
Ditto for the cheese. A thin slice on top of each cutlet or heaping handfuls of shredded cheese—whatever you like.