Preheat oven to 400 degrees F and grease a large pie pan or 10 inch springform pan with the butter.
Bring a large pot of salted water to a boil. Remove the tough stems from the chard and add to the boiling water. Cook until tender, 3-5 minutes or shorter for spinach. Rinse in cold water, drain, and chop.
In a medium bowl, beat together 4 of the eggs. Push the ricotta through a strainer into the bowl, being sure to scrap the underside of the strainer for excess ricotta. Mix in the Parmesan, bread crumbs, heavy cream, salt, pepper, chopped chard, and marjoram.
On a lightly floured surface, cut the puff pastry into 4 equal pieces. Roll one piece until thin and large enough to cover pan with excess hanging over the edges. Brush with olive oil and roll out another piece. Place over first piece at an angle so the overhanging edges are not together. Cover the other two pieces with a damp cloth.
Pour half of the chard ricotta mixture into the prepared pan over the puff pastry. Use a spoon to make 6 indentations in the chard mixture in a circle. Break an egg into each indentation. Season with salt and pepper and cover with remaining chard ricotta mixture. Use a wet spatula to smooth the top.
Roll another piece of puff pastry until thin and place over chard mixture. Brush with oil. Roll the remaining piece of puff pastry and place on top. Carefully crimp all of the edges the seal. Prick the surface a few times with a fork.
Bake in preheated oven until heated through and top is golden brown. Allow to sit for 10 minutes before slicing and serving. Serve hot or cold.