Remove the inner tender part of the palm hearts. Boil with some milk in salted water for 10 minutes and drain. Slice the palm hearts into 2 to 3 cm pieces. To prepare the bechamel sauce, combine the flour with the milk, melted butter and 50g of the grated cheese. Season with salt, pepper and nutmeg. Preheat the oven to 200°C for 15 minutes. Arrange the slices of the palm hearts on a greased oven dish and top with the béchamel sauce. Sprinkle with the rest of the grated cheese and the breadcrumbs. Bake for 30 minutes. Serve very hot.