This cheesy baked rutabaga and butternut squash casserole is a delicious vegetable gratin that can be served as a side dish or vegetarian main course. This simple veggie bake is layered with sweet and savory flavors you'll love.
1smallbutternut squashpeeled, seeded and thinly sliced
1smallrutabagapeeled and thinly sliced
melted fennel and leeksfrom above
bechamelfrom above
2cupsblend of grated cheesesuch as gruyere, comte, emmenthaler, mozzarella, monterey jack
Instructions
PREHEAT THE OVEN:
Arrange the oven rack in the center of the oven and Preheat the oven to 375° F.
FOR THE MELTED FENNEL AND LEEKS:
Trim the leeks of the root and tough green ends. Cut the leeks into 1/4" thick rounds and transfer to a medium bowl filled with cool water. Separate the leek rings and swish with the water to remove any grit or debris. Transfer to a salad spinner to dry the leeks.
Heat the olive oil and butter over medium heat and add the leeks and fennel, salt, pepper and thyme.
Stir to combine, cover with a tight fitting lid and reduce the heat to medium low, cooking until the vegetables are very soft, tender and translucent, about 10-12 minutes. Do not brown the vegetables. Set aside.
FOR THE BECHAMEL:
In a large saucepan, melt the butter over medium high heat. Sprinkle in the flour, mustard powder, garlic powder, kosher salt and pepper. Whisk to combine, so that there's no my dry floury bits.
Add warm milk a little at a time, stirring constantly. It will be a little clumpy at first, but as you continue to stir (or whisk), the clumpier bits will melt into the sauce. Stir constantly and bring the sauce to a boil for one minute or until the bechamel sauce thickens. Set aside.
ASSEMBLE THE GRATIN:
Spray a 2 quart casserole dish with vegetable spray. Spoon about 1/4 to 1/3 cup of bechamel sauce into the casserole and spread across the bottom.
Layer the bottom with about 1/3 of the slices of rutabaga and butternut squash, alternating between the two to get a good blend.
Top with 1/3 of the melted leeks, 1/3 of the bechamel and 1/3 of the cheese mixture.
Continue layering the casserole like this, ending with bechamel and cheese. Cut a piece of tin foil to cover the dish and spray with vegetable spray. Cover the casserole tightly with the foil (vegetable spray side down) and bake for one hour. (The vegetable spray will prevent the cheese and topping from sticking to the foil.
REDUCE THE OVEN TEMPERATURE TO 350° F.
Remove the foil and continue to bake for 30 minutes or until the vegetables are tender and yield when poked with a sharp knife.
Remove the gratin from the oven and let cool for 10 minutes before serving.
Note: Rutabaga and butternut squash contain more liquids than you might think and will leak into the casserole. It doesn't hurt anything, but if it bothers you, just tilt the casserole and spoon out the excess liquid (or use a turkey baster to suck it up). I soaked up about 1/3 cup of liquid from mine.