Heat olive oil in a wide pot over medium heat. Add the onion and sauté 5 minutes. Add salt and pepper.

Melt butter into the onion. Add garlic and roasted red bell pepper. Cook for 1 minute.

Add crushed red pepper and tomato paste. Mash the paste into the aromatics and cook for 2-3 minutes until it sizzles and deepens in color.

Add the cannellini beans and stir to coat. Season all over with salt and pepper.

Add the canned tomatoes and ¼ cup water. Bring to a boil and then reduce heat to low and simmer for 20 minutes until the sauce thickens and reduces slightly. Taste and add salt, pepper, and a pinch of sugar if needed.

Meanwhile, bring a large pot of salted water to a boil. Cook the spaghetti until al dente. Reserve 1/2 cup pasta cooking water and then drain the spaghetti. Set aside.

Stir in the parsley, basil, and lemon juice, then add the baby spinach. As soon as the spinach is wilted, add the pecorino Romano and stir until melted.

Add the spaghetti and toss it with the sauce, adding pasta water as needed.

Divide between bowls and garnish with more basil if you like. Enjoy!