If you are going to use dried morels, soak them in cold water for 1 hour, then strain. Make a tart pastry. Sift 1 1/2 cups flour on the table, make a well in the center, add a pinch salt, 1/2 cup cubed butter and 3 tablespoons water. Work the flour and the wet ingredients together without overworking, adding more water only if necessary to make a coherent mass. Form into a round and refrigerate for 2 hours. If you use fresh morels, stem them and rinse in vinegared water. Dry them. Cut the ham into thin strips. Roll the dough out on a floured surface. Butter a tart pan and lay the pastry in it. Place the morels and ham on the pastry. Preheat the oven to 425F. Make a light roux by melting the rest of the butter and adding the flour. Stir and add the milk, whisking hard so that it will not lump. Off the heat, add the egg yolks and cream, salt and pepper. Pour the mixture into the pastry and bake for 45 minutes. Serve immediately.