from Heidi Swanson, of the blog 101 Cookbooks:
I used a dozen big, chubby fresh tortelli here. You can certainly use ravioli. The ones I used were stuffed with ricotta al limone, but a bit later in the year I can imagine substituting winter squash / pumpkin tortelli/tortellini/raviolis - about 1/3 pound / 150g for 2 servings.
one dozen fresh tortelli pasta
4 tablespoons unsalted butter
1 tablespoons aged balsamic vinegar
fine grain sea salt
grated zest of one lemon
2 - 3 big handfuls of torn arugula or other bitter/spicy greens
plenty of grated fresh pecorino or Parmesan cheese
Bring a large pot of water to a boil. Cook tortelli per package instructions, or until the pasta floats, in well-salted water. Then drain, reserving a small cup of the pasta water.
In the meantime, place the butter in a skillet or saucepan over medium heat. Cook until the butter has browned and is very fragrant and nutty smelling. Remove from heat, and let it cool off for a minute or so. Whisk in the vinegar, a couple pinches of salt, and most of the lemon zest.
Add the cooked pasta to the brown butter pan and toss gently. Add a tiny, tiny splash of the reserved pasta water and toss again. Add the arugula, then turn out immediately into individual bowls or a serving platter topped with a bit of cheese and the remaining lemon zest.