Preheat the oven to 350 degrees . Grease a 9-inch pie pan and set aside. In a large saucepan of boiling salted water, cook the chard until softened, about 2 minutes. Drain in a colander, pressing down to release the excess liquid. Transfer the chard to a food processor and pulse until coarsely chopped.
Transfer the chard to a large bowl and beat in the egg yolks, cream and parmesan until combined; season with salt and pepper. Scrape the mixture into the prepared pan and bake until set, about 45 minutes. Slice and serve with the toast.