Preheat oven to 400°F
Melt 6 tablespoons of butter and allow to cool slightly. Add to a mixing bowl, stir in the beer.
Whisk in the egg, sugar, and vanilla.
Add the flour, baking powder, and salt, stir until just combined.
Add the remaining 2 tablespoons butter to a 9-inch cast iron skillet. Add to the oven until the butter is melted.
Remove the skillet and swirl to distribute the butter.
Pour the batter into the pan in an even layer. Top with the frozen berries.
Bake for 35-40 minutes, or until the center has set and the edges are a dark golden brown.
Remove from oven allow to cool.
Top with whipped cream for serving.
