Melt the butter and vegetable oil in a big skillet over medium heat. Once hot, add your sliced onions and sprinkle the kosher salt all over. Stir to coat and start mellowing out.
2 tablespoons Vegetable oil, 6 large Sweet onions, 2 teaspoons Kosher salt
Cook onions low and slow, stirring every now and then until they turn deep brown. It takes about 25 to 30 minutes.
6 large Sweet onions
When onions look just right, sprinkle flour over them and stir for a minute or two. Cook out raw flour taste for a silky sauce.
¼ cup All-purpose flour
Slowly add stock bit by bit, stirring constantly so no lumps form. The sauce will start to thicken.
¾ cup Stock
Lower the heat and stir in heavy cream and milk until everything is smooth and creamy.
2 cups Heavy cream, 2 cups Whole milk
Add cooked pasta to the cheesy onion sauce and mix it well. Add thyme leaves and stir once more.
1 pound Fusilli pasta, 4 sprigs Thyme
Transfer to a baking dish. Top with extra cheese if desired. Broil for about five minutes, until topping is bubbly with a golden brown crust.
1 ½ cups Grated provolone cheese, 1 ½ cups Grated Gruyere cheese
Spread butter on each baguette slice. Divide cheese between slices, sprinkle thyme leaves. Broil for 2-3 minutes or until bread is golden brown and crunchy.