Heat oven to 425°. Put medium sized (9 or 10 inches) cast-iron skillet in the oven to heat.
Beat eggs with milk, flour, sugar, salt and lemon zest. Batter will be thin. When oven is hot, remove pan and add butter, tipping pan to coat the pan’s bottom and sides as the butter melts. Pour most of the butter into batter and beat briefly. Pour batter into pan and bake 15 to 20 minutes, or until the edges are puffed and deep brown. Remove from oven and sprinkle with sugar of choice. The dramatic puff will begin to fall almost immediately when it’s removed from the oven. Sprinkle generously with sugar and provide lemon wedges for diners to squeeze juice over their pieces. Serves 3 to 4.
New England Baby: Eliminate lemon zest if you want. Serve Dutch Baby with butter and maple syrup
Summer Baby: Peel and slice a fresh peach. Cook it until soft in the skillet with a little butter and sugar (add a few blueberries if you have them). Pour batter over top and bake as directed.
Autumn Baby: Eliminate lemon zest and add 1 teaspoon of cinnamon (or pumpkin pie spice). Pour over 1 apple sliced and stewed with a little brown sugar and butter in the bottom of the skillet. Bake as directed.
Savory Baby: Eliminate lemon and sugar. Increase salt to ¾ teaspoon. Mix 2 tablespoons of fresh herbs (chives, oregano, basil, parsley) into the batter. Pour batter into pan and sprinkle with 2 tablespoons grated hard cheese, like Parmesan or Romano. Serve with a side of salsa or sautéed mushrooms.