Bring a large pot of salted water to a boil, then add spaghettini and cook to al dente as per package.
2 tbsp salt (for water), 250 g spaghettini
Drain the spaghettini over the sink, keeping at least ½ cup of pasta water in a heat safe bowl or jar and setting aside. Rinse the pasta with cold water and set aside.
1/2 cup pasta water
Add oil to the large pot and place it over low heat. Next, add the onions and cook until aromatic and translucent (about 8-10 minutes).
2 tbsp oil, 1 medium red onion or 2 shallots
Add tomatoes, garlic and salt to the pot and cook for another 12 minutes on low-medium heat, stirring frequently until the tomatoes soften and burst.
2 large garlic cloves or 4 small, 24 sungold or other small, sweet cherry tomato variety, 2 pinches salt
With a wooden spoon or spatula, press on the tomatoes until the soft seeds and juices come out of them. Add the butter and herbs to the pot, then reduce to heat to low. Stir until the butter melts and blends with the tomatoes, creating a smooth, rich sauce.
4 tbsp butter, 3-4 tbsp herbs (thyme, basil, dill, etc., or a mix)
Add the pasta to the pot and gently fold until the tomato, butter, and herbs coat the noodles.
Slowly stir in a little pasta water at a time until the sauce becomes velvety and smooth, but not too thin. The sauce should coat the back of a spoon and cling nicely to the pasta – you may end up using all of the pasta water.
1/2 cup pasta water
Taste the pasta and add salt as needed. Top the pasta with a local hard cheese, pepper, and extra herbs as desired. Serve immediately.
