Steam the spinach until wilted. Microwave for 3 minutes without added water.

Heat olive oil in a skillet over medium heat.

Chop the onion, shallots, and garlic. Sauté in the skillet for a few minutes until softened, being careful not to brown.

Add the diced and crushed tomatoes, most of the chopped fresh basil, and most of the dried oregano, salt, and pepper to the skillet.

Simmer the tomato sauce while preparing the filling.

In a bowl, mix the steamed spinach, ricotta cheese, remaining oregano, and beaten egg until well combined.

Slice the chicken breasts horizontally into thin, palm-sized pieces, or use scallopini.

Place a spoonful of the spinach and ricotta filling in the center of each chicken slice and roll it up.

Place the filled chicken rolls in a baking pan.

Cover the chicken rolls with the tomato sauce.

Bake in a preheated oven at 350°F (175°C) for 40 minutes.

Optionally, sprinkle shredded fat-free mozzarella cheese over the chicken rolls during the last 5 minutes of cooking.