6 Tbsp. olive oil (or less)
4 cups chopped onion
8 cups packed chopped swiss chard (keep stems and leaves separate)
3/4 to 1 lb penne or other short substantial pasta
1/2 to 3/4 lb crumbled feta cheese
salt and pepper
Cook onions about 10 minutes over medium heat. Start pasta water.
Add chopped chard stems and cook for 5 minutes. Add chopped chard leaves to pan and cook for an additional 10 minutes.
Cook pasta al dente.
Just as pasta is close to done, add feta to greens mixture (over low heat).
Add pasta to greens mixture, mixture thoroughly while heating for a few minutes.
Salt and pepper to taste.