This recipe is adapted from Marcella Says, by Italian cooking authority Marcella Hazan.

I added some of the barley cooking water to the soup. I found that its soothing quality tempered the squash and rapini’s sweet and bitter flavors.

Steps

1. Preheat oven to 425 degrees.
2. Toss squash cubes in the tablespoon of extra-virgin olive oil and add salt. Roast on a baking sheet lined with foil. Stir occasionally. The squash is done when it is completely tender.
3. Meanwhile, parboil rapini in 2 quarts salted water until al dente. Plunge rapini into ice water to stop the cooking. Reserve the cooking water. Cool rapini for no more than one minute, then drain well. Squeeze out excess water.
4. Put barley in a saucepan with the bay leaf and salt; add cold water to cover by two inches. Bring to a boil and then simmer until barley is almost tender, approximately 20 to 30 minutes. Add additional water if necessary. Drain barley, reserving the cooking water. Discard bay leaf.
5. Heat a soup pot over medium-low heat. Add the 3 tablespoons olive oil. Sauté garlic until lightly golden, then add chile flakes and rapini. Stir to combine. Sauté rapini, stirring, until it absorbs the flavor of the garlicky olive oil and loses its bitter edge.
6. Add squash and roughly mash it with a potato masher or a wooden spoon. Add enough cooking liquid, alternating between the rapini cooking water and the barley cooking water, to thin the squash-and-rapini mixture into a soup. Start with small amounts of each liquid and taste as you go; too much rapini cooking water will make the soup bitter. (And remember that you are adding salt to the soup with each addition of the cooking liquids.) Add plain water if necessary. Finally, add the barley and bring the soup to a simmer. Cook for a few minutes to combine. Adjust the seasoning.
7. Serve with a drizzle of olive oil and grated Parmesan, if desired.