Prep the chicken: Pat the chicken breasts dry with paper towels. In a small bowl, mix the salt, pepper, garlic powder, and Italian seasoning. Sprinkle evenly over both sides of the chicken.

Make the coating: In a shallow dish, combine the breadcrumbs with 1/4 cup of the grated Parmesan. In a second shallow dish, beat the egg.

Coat the chicken: Dip each chicken breast in the egg, then press into the breadcrumb mixture to coat both sides. Shake off excess crumbs.

Optional sear: For extra flavor and texture, heat the olive oil in a skillet over medium-high heat. Sear the chicken for 1–2 minutes per side, just until lightly golden. This step is optional but adds a subtle crust.

Layer in the slow cooker: Spread 1 cup of marinara on the bottom of the slow cooker. Place the chicken in a single layer on top. Spoon the remaining marinara over the chicken, making sure it’s mostly covered.

Cook: Cover and cook on Low for 3–4 hours or High for 2–2.5 hours, until the chicken reaches an internal temperature of 165°F and is tender but not falling apart.

Add the cheese: Sprinkle the mozzarella and remaining 1/4 cup Parmesan over the chicken. Cover and cook for another 10–15 minutes, until the cheese is melted and bubbly.

Finish and serve: Garnish with chopped basil or parsley. Serve over cooked spaghetti or with a side of steamed vegetables and garlic bread.