Preheat the oven to 400°F. Heat a 10-inch cast iron skillet (or oven safe skillet) until hot. Add butter and let melt in the skillet, watch carefully so that it doesn't burn or become too brown.
Meanwhile, whisk together the eggs, flour, milk maple syrup, salt, and vanilla until completely smooth. You could also use a blender for this process too.
Once the butter has melted and the skillet is hot, immediately pour the pancake batter into the hot skillet and transfer to the preheated oven.
Bake for 18 to 24 minutes until the oven pancake is puffed and nicely golden.
Remove from the oven and top with butter, additional maple syrup, fruit and berries, or whatever if your favorite. Cut into wedges and serve immediately.
Notes
Whisking the batter: Beat the eggs thoroughly by hand or in a blender. A well-mixed batter helps the pancake puff tall in the oven.
Hot skillet: Preheat your skillet in the oven before adding the batter. The hot pan + melted butter ensures a dramatic rise and crisp edges.
Sweeteners: This recipe uses maple syrup or honey for natural sweetness. Either works equally well — maple syrup adds a caramel note, and honey is more floral.
Serving: Serve immediately after baking. A German pancake will deflate as it cools, which is part of its custardy charm.