It's great when the kids get together to cook with friends. It creates healthy lifelong eating habits and just a nice pastime for teens. Here my son and his friends made a list and shopped for all of the ingredients themselves. They chose to make a Mac n' cheese with some sausage. To make it vegetarian you could roast and and add cubed butternut squash (say about a half a pound) instead of the sausage. Easy to make twos version here.
one pound of pasta
4 ounces of gruyere
4 ounces of cheddar
3 ounces of parmesan
salt and pepper to taste
1 cup of milk
1/2 a cup of pasta water
1/2 a pound of sausage (optional)
While pasta is boiling, shred the cheeses. After draining the pasta and reserving 1/2 a cup of the cooking liquid, add pasta back to pot. Add milk and slowly mix in cheese. add salt and pepper and add pasta water at the end to bring it all together. If making sausage, cook it in a skillet until browned and add it in.