Preheat the oven to 400F. Separate the eggs into two bowls—the whites in one, yolks in another. Whisk the milk and a tablespoon of the sugar into the yolks. Beat the whites until frothy, add the other tablespoon of sugar and whip until you have softly stiff peaks.
Stir the flour, baking powder and salt into the yolk-milk mixture and gently fold in the egg whites, maintaining as much volume as you can. Set a heavy 9 or 10-inch skillet (10 is better) over medium heat, add a chunk of butter (about 2 Tbsp), and when it melts and gets foamy, pour in the batter. Cook for about a minute, then transfer to the oven and bake for about 10 minutes, until it’s puffed and golden but not quite set—you want it a bit soft and custardy in the middle.
Take the pan out of the oven and cut the pancake into pieces with two flippers or spatulas. Often the pancake is cut into quarters to make it easier to handle— each piece is flipped before it’s torn, or the whole thing is inverted onto a cutting board. However you want to do it, pull it apart into about 1-inch pieces, and don’t worry about keeping it tidy.
Add another chunk of butter to the pan, set it back over medium heat and toss the pieces around, almost like scrambling eggs, until they’re golden and cooked through, with some crispy edges. Dust with icing sugar and serve warm with fruit compote or maple syrup. Serves about 4.