How to Make It
In a pot of salted boiling water, blanch the 2 cups of arugula for 30 seconds. Using tongs, transfer the arugula to a colander and rinse under cold water. Squeeze the arugula dry and transfer to a blender. Add the garlic and almonds and pulse until finely chopped. With the blender on, gradually add the olive oil in a slow steady stream; season with salt.
Add the pappardelle to the boiling water and cook until al dente. Drain, reserving 1/2 cup of the pasta water.
Meanwhile, in a large skillet, cook the pancetta over moderate heat, stirring, until browned, 5 minutes. Spoon off most of the fat. Add the onion to the skillet and cook until translucent, 5 minutes. Add the corn and cook until crisp-tender, 1 to 2 minutes.
Add the pasta, reserved pasta water, pesto and butter to the skillet and cook, tossing, until the pasta is hot and evenly coated. Season with salt and transfer to a bowl. Garnish with arugula leaves and serve, passing grated cheese at the table.