"John's obsession is carbonara. Adding butternut squash puree gives this riff delicious fall flavor." —Rach
Bring a large pot of water to boil for the pasta.
In a large skillet, heat the EVOO, three turns of the pan, over medium-high. Add the pancetta and cook until the fat renders, 3 to 4 minutes. Add the shallot, garlic, and sage; season to taste with salt and pepper. Stir for another 3 to 4 minutes, then add the wine and let the liquid reduce for a minute or so. Reduce the heat to low to keep warm.
In a medium bowl, whisk the squash puree and egg yolks. Season with salt, pepper, and nutmeg.
Salt the boiling water, add the pasta, and cook for about 1 minute less than the package directions. Drain the pasta, reserving 1 cup of cooking water.
Slowly whisk the cooking water into the squash and yolks to temper the eggs. Toss the pasta in the skillet with the pancetta, add the squash mixture and the cheeses, and toss to coat. Stir until the sauce thickens slightly, about 2 minutes; season.