Liven up tomato sauce with fresh spinach, basil, Parmesan and red pepper flakes and toss in noodles to make a hearty one-pot pasta.
In a Dutch oven or other heavy-bottomed pot with a lid, heat the oil over medium-high heat. Add the onion and cook, stirring frequently, until the onion is tender and begins to brown, about 5 minutes. Add the garlic and cook, stirring frequently, for 1 minute.
Add the tomatoes and their juices, chicken stock, 1/2 cup water, Italian seasoning and red pepper flakes and stir to combine. Add the bucatini or spaghetti, breaking to fit if necessary and stirring to separate the noodles.
Bring to a boil, cover, reduce the heat and simmer for about 8 minutes, until the noodles are al dente. Stir in the spinach in batches, letting each batch wilt.
Remove from the heat and stir in the basil and grated Parmesan. Season to taste with salt and serve.