Combine ricotta cheese, mozzarella, grated parmesan, finely chopped mushrooms, chopped sundried tomatoes, and tightly packed spinach in a bowl. Season the mixture with salt and pepper, stirring until everything is evenly distributed. This filling is the heart of the dish, so take a moment to ensure the ingredients are well incorporated and the spinach is broken up throughout.

Preheat oven to 400°F and lightly grease a baking dish with olive oil. In one shallow bowl, whisk together egg whites until slightly foamy. In a second shallow bowl, combine breadcrumbs with garlic powder, salt, and pepper. Season the pounded chicken cutlets with salt and pepper on both sides.

Lay one seasoned chicken cutlet flat and spread 2-3 tablespoons of the spinach and cheese filling from Step 1 across the center, leaving a small border on all sides. Roll the chicken tightly from one end to the other, tucking in the sides as you go. I find that rolling tightly helps the filling stay inside during baking. Repeat with remaining chicken cutlets and filling. Working one at a time, dip each roll into the egg white mixture, allowing excess to drip off, then roll in the seasoned breadcrumb mixture from Step 2 until fully coated.

Arrange the breaded chicken rolls seam-side down in the prepared baking dish. Bake at 400°F for 25 minutes until the chicken is cooked through and the exterior is golden brown. The internal temperature should reach 165°F when checked with a meat thermometer.

Remove the baking dish from the oven and spoon marinara sauce over each chicken roll. Top evenly with mozzarella cheese. Return to the oven and bake for an additional 5-10 minutes until the cheese is melted and bubbly and the sauce is heated through.

Remove from the oven and let rest for 2-3 minutes before serving. Garnish with fresh chopped basil. I always add the basil after cooking rather than before—it keeps the herb bright and fragrant instead of becoming muted from the heat.