If you make homemade béchamel sauce, make it first and set it aside for later.
Peel and cut the onions into¼ inch slices. Add the onions to a large pan with the sugar and cook at high heat until they start to brown. Add the white wine and let the alcohol evaporate.
Lower the heat and add the water. Season with salt, pepper thyme, and sage. Cook for about 10 minutes, until the onions are soft.
Meanwhile, bring a large pot of salted water to boil and toss the pasta. Cook for 3-4 minutes less than what is mentioned in the package instructions. It will finish cooking in the oven.
Add the pasta to the pan with the onions and add the béchamel sauce. If the white sauce is too dense, add some milk. It needs to be quite loose as the pasta will absorb the liquid while cooking in the oven.
Mix well, then transfer the pasta to a baking dish. Mine is a 10.5x8 inches (26x20 cm) oval dish. Sprinkle the grated cheese and the Parmigiano cheese on top.
Bake in the preheated oven for 15-20 minutes or until golden brown on top.
How to make the Béchamel sauce: In a pan, melt ½ tablespoon of butter, then add ½ tablespoon of flour and mix well to create a creamy paste, called roux. Add 1 cup of milk (either cold or room temperature will work fine) and mix well with a whisk until the roux is fully dissolved. Bring to a simmer then turn down the heat and whisk slowly until the sauce thickens enough to coat a spoon. Season with salt and black pepper and set aside.What kind of cheese should I use? Any cheese that melts will work great for this recipe. I used grated Gouda cheese, but you can also use Gruyere, Fontina, Emmentaler, Comte, and so on. The cheese will create a layer on top of the pasta which will prevent the pasta from drying out.