Dutch Baby pancake

½ cup milk warmed to room temp
3 large eggs straight from the coop or room temp
½ cup all-purpose flour, spooned into measuring cup and leveled-off
1 tablespoon maple syrup, plus more for serving
¼ teaspoon salt
½ teaspoon vanilla extract
3 tablespoons unsalted butter
Confectioners' sugar, for serving (optional)
Fresh berries or jam, for serving (optional)

Preheat oven to 400°F and set an oven rack in the middle position. Put a 10-inch cast iron skillet or oven-safe nonstick pan into the oven and heat for at least 5 minutes.
In a blender, combine the eggs, flour, milk, 1 tablespoon maple syrup, the salt, and vanilla. Blend until completely smooth, scraping down the sides of the blender jar as necessary, about 30 seconds.
Open the oven door and drop the butter into the preheated skillet. Close the oven and allow the butter to melt, about 2 minutes (do not let it burn). Carefully remove the hot skillet from the oven and place an oven mitt or dishtowel over the handle to remind yourself that it's hot. Pour the batter into the buttered skillet and carefully place the skillet back into the center of the oven. Nobody puts Baby in the corner. Bake for about 20 minutes, until puffed and golden. No running in the kitchen.  Carefully remove the skillet from the oven (again, place an oven mitt or dishtowel over the handle to remind yourself that it's hot). Dust the Baby with confectioners' sugar and top with berries, if desired, then cut into wedges and serve with maple syrup.