Pasta with Chard and Feta Cheese

6 tablespoons olive oil
4 cups chopped fresh onions
Washed and coarsely chopped greens -- about 7 or 8 cups
Salt to taste
3/4 pound penne, fusilli, shells, or some comparable short pasta
1/2 to 3/4 lb. feta cheese, crumbled
Freshly grated parmesan or asiago cheese (optional)
Freshly ground black pepper

Heat the olive oil in a deep skillet. Add onions and cook for about 10 minutes over medium heat, stirring occasionally. Meanwhile, put the pasta water up to boil. Add chopped greens to the skillet, salt lightly and stir until the greens wilt. Cover and cook 10 to 15 minutes over a medium to low heat.

Cook the pasta until al dente. Just as it becomes ready, add the crumbled feta cheese to the greens, with heat on low (or off). When the pasta is done, scoop it out with a strainer, drain it and add it directly to the pot full of sauce. Mix thoroughly. Cook the completed dish just slightly over a low heat for a few minutes. Add a small amount of grated cheese, if desired, and some black pepper. Serve immediately.