- 2 tablespoons olive oil
- 1/2 onion, chopped
- 1 teaspoon salt
- 1 teaspoon ground black pepper
- 1 cup chopped fresh parsley
- 4 cloves garlic, minced
- 1/2 cup grated Parmesan cheese
- 1 hard-boiled egg, chopped
- 1 pinch salt and ground black pepper
- 1 tablespoon olive oil, or more if needed
- 2 pounds flank steak, pounded until thin
- 5 toothpicks, or as needed
- 1 tablespoon olive oil
- 1 (8 ounce) can tomato sauce
- 1 pinch white sugar
- 1 tomato, chopped, or more as needed
- Heat 2 tablespoons olive oil in a large skillet over medium heat; cook and stir onion in the hot oil until tender, about 10 minutes. Season with 1 teaspoon salt and 1 teaspoon pepper.
- Mix parsley, garlic, Parmesan cheese, egg, 1 pinch salt, and 1 pinch pepper in a bowl; drizzle in about 1 tablespoon olive oil, while continually stirring, until a sticky consistency is reached.
- Spread parsley filling in a thin layer atop flank steak; roll steak in a jelly-roll style and fasten ending piece to steak with toothpicks to contain filling.
- Pour remaining 1 tablespoon olive oil into skillet with onions over medium heat; cook steak roll in the onion mixture, turning steak until browned on all sides, 2 to 3 minutes per side. Add tomato sauce, sugar, and chopped tomato to the steak mixture; simmer over very low heat until steak is cooked through and sauce has slightly reduced, 1 to 1 1/2 hours.