Beet greens and rice gratin

This is another one of those dishes that's good either hot or cold.

Notes: I used mozzarella instead of Gruyere (and added more Parmesan), and I skipped the blanching/steaming set. I just threw the raw beet greens directly into the pan with the onion and garlic and let them cook until wilted.

From the New York Times:

1 generous bunch beet greens, stemmed and washed
2 tablespoons extra virgin olive oil
1 medium onion, chopped
2 large garlic cloves, minced
Salt to taste
1 teaspoon fresh thyme leaves or 1/2 teaspoon dried thyme
3 eggs
1/2 cup low-fat milk (2 percent)
Freshly ground pepper
1 cup cooked brown rice, arborio rice or Calrose rice
2 ounces Gruyère cheese, grated (1/2 cup, tightly packed)
2 tablespoons freshly grated Parmesan
1/4 cup bread crumbs (optional)

Preheat the oven to 375 degrees. Oil a 2-quart gratin dish with olive oil. Either blanch the beet greens for 1 minute in a large pot of generously salted boiling water, or steam over an inch of boiling water for 2 to 5 minutes, until wilted and tender. Rinse with cold water, squeeze out water and chop medium-fine. Set aside.

Heat 1 tablespoon of the oil over medium heat in a large, heavy skillet and add the onion. Cook, stirring, until tender, about 5 minutes, and add the garlic and a generous pinch of salt. Cook, stirring, until the garlic is fragrant, about 30 seconds. Stir in the cooked greens and the thyme and toss together. Season to taste with salt and pepper. Remove from the heat.

In a large bowl, beat together the eggs and milk. Add 1/2 teaspoon salt and freshly ground pepper to taste. Stir in the greens mixture, the rice and the cheeses and mix together well. Scrape into the oiled baking dish. Sprinkle the bread crumbs over the top. Drizzle on the remaining tablespoon of oil.

Bake 35 to 40 minutes, until sizzling and lightly browned on the top and sides. Remove from the heat and allow to sit for at least 10 minutes before serving.