Chard and Onion Omelet

from Deborah Madison

3 tbsp olive oil
1 large red or white onion, quartered and thinly sliced crosswise
1 bunch chard, leaves only, chopped
salt and pepper
1 garlic clove or use several green garlic
6 to 8 eggs, lightly beaten
2 tbsp chopped parsely
2 tsp chopped thyme
1 cup grated gruyere
2 tbsp freshly grated parmesan

Heat 2 tbsp of the oil in a 10inch skillet, add the onion and cook over low heat, stirring occasionally, until completely soft, but not colored, about 15 minutes. Add the chard and continue cooking, stirring occasionally, until all the moisture has cooked off and the chard in tender, about 15 minutes. Season well with salt and pepper.
Meanwhile, chop garlic finely with a few pinches of salt, then stir it into the eggs along with the herbs. Combine the chard mixture with the eggs and stir in the gruyere and half the parmesan. Preheat the broiler. Heat the remaining oil in the skillet and, when it is hot, add the eggs. Give a stir and keep the heat at medium-high for about a minute, then turn it to low. Cook until the eggs are set but a little moist on top, 10 to 15 minutes. Add the remaining parmesan and broil 4 to 6 inches from the heat, until browned.