steps for preparation

Bring a large pot of well-salted water to a boil. Cook pasta until 1minute shy of al dente, according to the package directions. Drain, reserving 1/2 cup of pasta water.
Meanwhile, heat oil in large sauté pan over medium heat; add scallion whites and a pinch of salt and cook until soft, 3 minutes. Add 1/4 cup water and all but 1/4 cup corn; simmer until corn is heated through and almost tender, 3 to 5 minutes. Add 1/4 teaspoon salt and 1/4 teaspoon pepper, transfer to a blender, and purée mixture until smooth, adding a little extra water if needed to get a thick but pourable texture.
Heat the same skillet over high heat. Add butter and let melt. Add reserved 1/4 cup corn and cook until tender, 1 to 2 minutes. (It’s O.K. if the butter browns; that deepens the flavours.
Reduce heat to medium. Add pasta and half the reserved pasta cooking water, tossing to coat. Cook for 1 minute, then add a little more of the pasta cooking water if the mixture seems too thick. Stir in 1/4 cup of the scallion greens, the Parmesan, the herbs, the red pepper flakes, 1/4 teaspoon salt and 1/4 teaspoon pepper. Sprinkle with fresh lemon juice to taste. Transfer to warm pasta bowls and garnish with more scallions, herbs, a drizzle of olive oil and black pepper.