Preheat the oven to 400°F.
Place 1 stick of butter in a large Pyrex baking dish and put it in the preheated oven just until the butter is melted. Be careful not to leave the dish in the oven too long. Once the butter has melted, remove the baking dish from the oven.
Add the room-temperature eggs to a blender, KitchenAid mixer, or large bowl if using a handheld electric mixer. Beat on high for 1 minute.
Slowly pour in the room-temperature milk while continuing to mix.
Add the flour and salt and mix until incorporated.
Once all the ingredients have been added, mix on high for 1 additional minute. The batter should be smooth and well combined.
Carefully pour the batter into the baking dish with the melted butter.
Return the dish to the oven and bake at 400°F for 30 minutes, until the Dutch Baby is beautifully puffed and golden around the edges.
The Dutch Baby will begin to settle as it cools—that's completely normal. Slice and serve warm with your favorite toppings.