Creamy, cheesy, saucy, gratin. It almost doesn’t matter what kind of vegetables you put into it, it comes out of the oven tasting like a heavy dream.
Gratin is pronounced grah-tanh, although that’s not quite the right way to write the pronunciation, as you don’t really pronounce the letter n.
A gratin is a kind of casserole made from sliced vegetables, usually root vegetables like potatoes and onions, or sqaush. But gratins can be made from any vegetables that go well with an Emmentaler or Gruyere cream sauce.
Butternut Squash et Pomme de Terre Gratin
The size of your gratin will be dictated by the amount of vegetables you have on hand. The gratin in the photo above was only two small servings, made in a small Pyrex bowl.
Preheat the oven to 350 degrees.
Equal amount of potatoes – Yukon Golds will work well for this because they are sturdy and won’t fall apart
Emmentaler and/or Gruyere cheese, shredded, enough to cover the casserole dish + 1/4 cup for the sauce.
1 cup or 1-1/2 cups of milk
1 – 2 tablesppons of flour
2 tablespoons of butter
To prepare the squash in advance:
Bake the butternut squash in the oven at 350 degrees, just until a fork will go through it and the skin will peel off. You can do this up to a day ahead of time and store in the refrigerator until you are ready to use it.
Putting the gratin together:
Peel the butternut squash.
Cut the squash in half lengthwise, and then cut each half into uniform slices about 1/8 of an inch thick.
Peel the potatoes.
Slice the potatoes evenly, about an 1/8 of an inch thick, so they are the same width/size as the squash slices.
Have a buttered oven-proof casserole dish at the ready.
Layer one layer of squash, then one layer of potatoes, then repeat until all the vegetables are layered in the dish.
You need a whisk to make this sauce.
Have the milk in a measuring cup or pitcher, sitting ready next to the stove.
In a sauce pan or saucier, on a very low flame, make a roux out of the butter and flour by first melting a couple of tablespoons of butter with ground pepper, a pinch of dried basil and a pinch of thyme.
Add the 1 – 2 tablespoons of flour to the melted butter.
With the whisk, thoroughly mix the butter with the flour, and let it cook until almost turning golden.
Be careful to keep an eye on it so as not to burn the pan.
Continue whisking and slowly pour a little of the milk slowly into the pan while whisking.
The flour will absorb the milk immediately, but keep whisking and keep slowly pouring in the milk.
Eventually the sauce will be thinned out.
Slowly simmer the sauce, while whisking continually.
DO NOT BOIL!
Add a little – about a 1/4 cup – shredded Emmentaler and/or Gruyere to the sauce.
Whisk some more until the cheese melts.
The sauce will start to thicken.
Take the sauce off of the flame.
Back to the Casserole:
Cover the top of the squash and potatoes with shredded Emmentaler or Gruyere cheese.
Pour the sauce over the potatoes and squash.
Put in the oven uncovered for about 1/2 an hour or 45 minutes.
Gratin is done when the sauce is bubbling and the top is a golden brown.