Fill a large pot with water and set it over high heat to boil.

While the water heats, cut the broccoli into small florets, slice the scallions and keep the white and green parts separate, chop the garlic, and chop the peanuts if they are not already chopped.

Put the peanut butter, soy sauce, and rice vinegar into a medium bowl. Stir them together until they form a thick paste, then set the bowl near the stove.

When the water is boiling, add a generous pinch of salt and put the spaghetti into the pot.

Stir the spaghetti for the first few seconds so the noodles do not stick together. Cook it until it is about 3 minutes away from the package time for tender pasta.

Add the broccoli florets to the pot with the spaghetti. Cook until the broccoli is bright green and the pasta is tender, about 3 minutes more.

Dip a measuring cup into the pot and reserve 1 1/2 cups of the pasta cooking water.

Drain the spaghetti and broccoli together in a colander. Do not rinse them.

Set a large skillet over medium heat and add the neutral oil.

Add the scallion whites to the skillet and cook until they soften, about 1 minute.

Add the garlic to the skillet and cook until fragrant, about 30 seconds.

Add the chili crisp to the skillet and stir for about 15 seconds to wake up its flavor.