Summer Squash and Rice Gratin

2 lbs. squash, coarsely grated (any variety will work -- zucchini, Zephyr, yellow squash or pattypan)
1 sweet yellow onion, finely diced
1-1/2 cups brown rice
2 cups white sauce (see below)
cheddar cheese, optional (or any kind of cheese would work)
grated parmesan cheese, optional
salt & pepper to taste

Boil the rice in 2-1/2 cups water, until water is absorbed and rice is tender. In the meantime, toss the grated squash with 1 teaspoon salt and set aside in a colander to drain.

To make the sauce, melt 4 tablespoons butter in a small pan. Stir in 4 tablespoons white flour, then slowly add 2 cups milk, stirring constantly until the milk has thickened. If desired, add a generous handful of grated cheese and stir until melted. (As an alternative, if you'd rather not make it a cheese-y sauce, add a pinch or two of whatever dried herbs suit your fancy.) Sprinkle in salt and pepper, to taste, and stir in a little more milk if it seems too thick.

Preheat oven to 375. Heat a couple tablespoons of olive oil in a wide skillet. Cook onions over medium heat until softened, then add the drained squash and cook, stirring frequently, until the pan is dry and the squash has begun to color. Taste for salt and add some pepper, if you want. Combine the rice, squash mixture and sauce, and smooth it into a 2-quart casserole. Top with grated parmesan, if desired, and bake until top is golden, about 25 minutes.