Bring the water to boil. Season the water with salt generously.
While the water is coming to boil, over medium-to-low heat in a medium sized skillet, melt the butter. Let the butter brown, this will take about 3-5 minutes. Watch it carefully, no need to stir.
While the butter has begun to melt and the water is now boiling, add the tortelli to the pasta water and cook the directed amount stated on the packaging (usually about 3-4 minutes).
When the butter has become brown, add the sage leaves as they will fry in a matter of seconds (3-5). Turn off the heat on the skillet with the butter. Add the cooked tortelli to the butter and toss gently with a spatula until all is covered and flavored well.
Serve by sliding the tortelli onto the bowls or dishes, grate fresh Parmigiana Reggiano over each dish (making sure the sage leaves are also included) and if you have toasted walnuts or pine nuts add those as well. C'est tous! Pair with a lovely glass of your favorite wine and enjoy!