In a large sauté pan or skillet, heat 1 tbsp of olive oil over medium heat. Add the chopped onion and cook for about 5 minutes, stirring occasionally, until softening, golden, and caramelized around the edges.
Add the Garlic
Crush the garlic cloves with your hands or a knife. Once the onion is soft, stir in the garlic cloves. Let it cook for about 60 seconds until fragrant, making sure it doesn't burn.
Simmer the Tomato Passata
Pour in the tomato passata and stir to combine. Fill the tomato passata bottle to half with water, close it, shake it to get the remaining sauce and add that to the pan. Bring the sauce to a simmer and let it cook down gently on low heat for 20-25 minutes, stirring occasionally, until the sauce has thickened.
Prepare the Beans
In the meantime, trim the ends of the Romano beans and cut them into manageable length, into two or three pieces lengthwise if they are very long. Bring a pot of salted water to a boil and cook the beans until tender, about 10 minutes. Drain and set aside.
Add the Romano Beans
Once the tomato sauce has reduced and is rich and fragrant, stir in the pre-cooked Romano beans. Coat them well in the sauce and let everything simmer together for another 5 minutes so the flavors can meld.
Taste and Adjust
Taste the beans and sauce, adjusting seasoning as needed.
Serve
Serve warm or at room temperature. Garnish with some more olive oil and fresh basil if desired.