Pat each chicken breast dry with paper towels and trim any fat or thin flaps so thickness is even.

If your breasts are uneven, place one between two pieces of plastic wrap and gently pound to an even thickness (about ½ inch). This helps them cook evenly in the crockpot.

Season both sides of each breast with salt, black pepper, garlic powder, onion powder, and a light sprinkle of Italian seasoning.

Pro tip: gently pounding the chicken makes a world of difference — it shortens the cooking time and keeps the texture consistent across all pieces.

In a mixing bowl combine the 1 cup seasoned breadcrumbs with the 2 tablespoons olive oil (or melted butter).

Add a tablespoon or two of the grated Parmesan into the crumbs for flavor (reserve the rest of the Parmesan for topping).

Stir until the crumbs are evenly moistened and hold together slightly when pressed.

Pro tip: if your breadcrumbs look dry, add the oil in small increments — you want them tacky, not greasy.

Press each seasoned chicken breast into the breadcrumb mixture, coating both sides and gently pressing the crumbs so they adhere. Shake off any excess.

If you prefer extra flavor and a bit of color, heat a skillet over medium-high heat with 1 tablespoon oil and quickly sear the breasts 1–2 minutes per side just until golden (this step is optional). Transfer the chicken to the crockpot after searing.

Pro tip: searing is optional but gives a richer flavor and nicer color — do it only if you have a hot pan and a minute to spare.

Pour about 1 cup of the marinara sauce into the bottom of your crockpot and spread it into an even layer (this prevents sticking and adds base flavor).

Arrange the coated chicken breasts in a single layer on top of the sauce. If your crockpot is crowded, slightly overlap but avoid stacking pieces directly on top of each other.

Spoon the remaining marinara sauce over the chicken, making sure each piece gets some sauce. Sprinkle the remaining grated Parmesan over the sauced chicken (save the mozzarella for the finish).

Pro tip: resist the urge to lift the lid while it’s cooking — every peek lets heat escape and can lengthen the cooking time.

Cover the crockpot and cook on LOW for 3–4 hours or HIGH for 2–3 hours, depending on your schedule and crockpot model. Cooking times vary slightly with appliance size and thickness of chicken.

Start checking toward the lower end of the time range: use an instant-read thermometer and make sure each breast reaches 165°F (74°C) in the thickest part. If you don’t have a thermometer, cut into the center—juices should run clear and the meat should be opaque, not pink.

Pro tip: a thermometer is the easiest way to avoid overcooking. Once it hits 165°F, it’s done — remove it promptly to prevent drying.

Once the chicken is cooked through, sprinkle the shredded mozzarella evenly over each breast (and a light additional dusting of Parmesan if you like).

Replace the lid and let the cheese melt on Warm for 10–15 minutes in the crockpot, or transfer the pieces to an oven-safe baking dish and broil 2–3 minutes (watching closely) to get a bubbly, golden top.

Pro tip: if broiling, place the rack about 6 inches from the broiler and keep the oven door slightly ajar — mozzarella can go from perfect to burnt very quickly.

Let the chicken rest 3–5 minutes after removing from heat so the juices settle and the cheese sets slightly.

Garnish with chopped fresh basil or parsley before serving.

Serving ideas (brief): spoon extra sauce from the crockpot over the chicken and serve over spaghetti, zucchini noodles, or inside a toasted roll for a hearty sandwich.