Bring a stockpot of water to a rapid boil.Season generously with kosher or sea salt. Add the bucatini and gently use the spoon to bend it into the water. Stir to make sure it doesn't stick to the bottom of the pot. Cook according to package directions. Reserve a cup of pasta water before draining the pasta into a colander.

Over medium heat, melt the butter and olive oil until the butter is melted. Add the onion and season with half each of the salt and pepper and saute for about 3-5 minutes.

Add in the the garlic right at the end of the onions cooking. Stir until you can smell them, about 30 seconds or so.

Pour in the white wine. Cook until the alcohol cooks off the wine for 2 minutes.

In the wine and onion skillet, stir in the mascarpone and mix until creamy. Pour in the passata, season with the remaining salt and pepper. Allow the sauce to thicken and simmer for about 15 minutes.

Use tongs to toss the cooked bucatini pasta into the skillet of sauce, until all the strands are coated. Add in some pasta water (start with ½ cup) as needed to loosen the sauce. Don't go too crazy as you don't want to dilute the flavor of the sauce too much.

Twirl onto warm plates or bowls. Top with fresh parmesan cheese and basil and a drizzle of spicy chili oil, if you choose.