Preheat the oven to 350 degrees F (175 degrees C). Butter a 10 inch pie plate using about 1 tablespoon of butter. Sprinkle bread crumbs into the pie dish and shake to coat evenly, discarding excess.
Pour the milk into a large saucepan and warm over medium heat. Add the salmon fillets and bring to a simmer. Cover and cook for about 10 minutes, or until salmon can be flaked with a fork.
Melt the remaining butter in a large skillet over medium heat. Add the onion and Swiss chard; cook and stir until tender and most of the liquid has evaporated. Season with salt, pepper, marjoram and nutmeg. Set aside to cool; you should have about one cup
of chard and onion.
Spread the chard mixture and flake the salmon into the prepared pie plate. In a medium bowl, whisk together the eggs and one cup of cooled milk from poaching the salmon. Pour into the pie dish.
Bake for 35 minutes in the preheated oven, or until the center is set. Cool slightly before serving.