Place the butter in a 9-in. pie plate; place in a 400° oven for 4-5 minutes or until melted. Tilt pie plate to evenly coat bottom and sides with butter.
In a small bowl, whisk the eggs and milk. In another small bowl, combine the flour and salt; whisk in egg mixture until smooth. Pour batter into prepared pie plate. Bake until sides are crisp and golden brown, 15-20 minutes.
Meanwhile, in a large bowl, gently combine the berries and marmalade. Sprinkle pancake with confectioners' sugar; fill with berry mixture. Serve immediately. If desired, serve with whipped cream.