Bring a large pot of water to a boil, meanwhile saute the onions in olive oil for 3-4 minutes or until opaque.
Add 4 cups of arugula and saute for 1 minute, add heavy cream and bring to a simmer, season with salt and pepper to taste.
Pour the mixture into a blender and puree on medium speed for 1 minute.
Add the sauce back to the pan and bring to a simmer, cook the pasta according to package directions, drain and toss with the sauce and the cherry tomatoes, finish with remaining arugula and cheese.
