This is the template that I use for most of my main-dish vegetable gratins. I like gratins hot, warm or at room temperature. I fold the aromatic vegetable filling into a mixture of eggs beaten with milk, salt, pepper and cheese, usually Gruyère, and then add rice or, in this case, corn.
03Heat 1 tablespoon olive oil in a medium skillet and add garlic. Cook, stirring, until fragrant, 30 seconds to a minute, then stir in rosemary, thyme and chopped blanched chard. Season with salt and pepper and stir over medium heat until chard is nicely coated with oil, about 1 minute. Remove from heat.
04In a large bowl, beat together eggs, milk and 1/2 teaspoon salt. Stir in chard mixture and Gruyère. Stir in corn and mix well. Scrape into prepared baking dish. Sprinkle Parmesan over top and drizzle with olive oil.
05Bake 35 to 40 minutes, until nicely browned on the top and sides. Allow to sit for at least 10 minutes before serving.