- 20 grams gim, often labeled as roasted seaweed
- 2 (4-inch) squares dasima or kombu (dried kelp)
- 1 tablespoon kosher salt
- 1 pound rigatoni
- 1 ½ cups heavy cream
- 1 small red onion, halved and thinly sliced
- 2 large garlic cloves, finely grated
- 1 teaspoon freshly ground black pepper, plus more to taste
- 1 teaspoon rice vinegar
- ½ pound asparagus, thinly sliced at an angle
- 1 tablespoon toasted sesame oil
- Flaky sea salt, for serving
- Fold the gim in half and, with very sharp kitchen shears or a chef’s knife, slice into thin strips. Set aside for serving.
- In a large pot, combine 1 dasima square with 8 cups cold tap water. Bring the water to a boil and season with the kosher salt. Tumble in the pasta and cook for half the time the package tells you is al dente. Reserve 1 cup of the pasta water. Drain the pasta, then add it back to the pot. (Discard the dasima.)
- Add the remaining dasima square, cream, red onion, garlic, black pepper and reserved pasta water to the pasta. Bring to a boil over high heat, then immediately reduce the heat to a gentle simmer. Stirring occasionally, cook the pasta until the onion-infused cream has thickened significantly, thinly coating the noodles, 4 to 5 minutes.
- Turn off the heat. Add the vinegar and asparagus, and stir to combine for 1 minute. The residual heat from the pasta will gently cook the asparagus to tender-crisp. Stir in the sesame oil and season with more black pepper, if desired. Divide the pasta among serving dishes, discarding the dasima, and shower with the reserved gim and sprinkle with flaky sea salt. Serve immediately, before the gim wilts and turns soggy.