This recipe comes from Vikingars Gästabud (The Viking Feast), and is for four servings.
Turn on the oven to 425°F (225°C). Whisk the batter together without the butter and stir in the berries. Melt the butter in a heat-resistant baking pan and pour it in the batter. Bake it in the middle of the oven for about 20-25 minutes until the pancake has a nice color. Cut it into pieces and serve with some jam.