Prepare the pasta according to box directions, drain and set aside.

Melt butter over medium heat in a large skillet.  Add all of the onions and cook 3-4minutes, stirring occasionally.

Season onions with salt and pepper.  Pour in half of the sherry and cook until reduced.

Carefully stir arugula into skillet.  Pour in the remaining sherry and cook 4-5minutes, until reduced.

When veggies are almost done, reheat the pasta pot over high heat.  Add in pasta, milk, and brie.  Stir to combine then cover for 3-4minutes.

Pour vegetable mixture into pasta mixture and stir to combine.

Serves 4-6