How to Make It
In a pot of salted boiling water, cook the corn until crisp-tender, 5 minutes. Let cool, then cut the kernels off the cobs.
Meanwhile, in a large cast-iron skillet, cook the scallions over high heat until charred on the bottom, about 3 minutes. Cut into 2-inch lengths.
In the same skillet, cook the pancetta over moderate heat, stirring occasionally, until browned, about 5 minutes. Using a slotted spoon, transfer to a paper towel–lined plate to drain. Pour off all but 1 tablespoon of fat from the skillet.
Heat 2 tablespoons of the oil in the skillet. Add the mushrooms and season with salt and pepper. Cook over moderately high heat, stirring occasionally, until browned, 5 to 7 minutes.
In a large bowl, whisk the lemon zest and juice with the honey, vinegar and remaining 1/4 cup plus 2 tablespoons of olive oil. Season the dressing with salt and pepper. Add the corn, scallions, pancetta, mushrooms, frisée and chives and toss to coat; season with salt and pepper. Top the salad with shaved Gruyère and serve.