Take the eggs out of the fridge about 20 minutes before you start so they are at room temperature. Measure all ingredients into small bowls and wipe your mixing bowl and beaters with a paper towel dampened with vinegar, then dry well.
Crack one egg at a time over a small bowl, then pass the yolk back and forth between the shell halves to let the white fall away. Slide the white into your large clean mixing bowl and the yolk into a second bowl.
Add the milk, vanilla extract, and salt to the bowl of yolks and whisk for about 30 seconds until smooth and slightly pale. Sift in the cake flour and baking powder, then stir gently until you have a thick, smooth batter with no dry streaks.
Add the white vinegar to the egg whites and beat on medium speed for 1 to 2 minutes until foamy. Increase to medium-high and add the sugar one tablespoon at a time, then keep whipping for 3 to 4 minutes until the meringue is thick, glossy, and holds a stiff peak.
Scoop about one third of the meringue into the yolk batter and whisk it in firmly to loosen the batter. Add half of the remaining meringue and fold gently with a rubber spatula, then add the last of the meringue and fold until no white streaks remain.
Place your nonstick pan over the lowest heat setting and let it warm for 2 minutes. Pour in the oil, then wipe it around the pan with a paper towel until only a thin film remains. If using ring molds, grease the insides well and set them in the pan now.
Spoon or pipe three mounds of batter into the pan, each about 1/3 cup, leaving space between them. Gently place a small dollop on top of each mound to build height without spreading or flattening the batter.
Drizzle 1 tablespoon of water into the empty spaces of the pan, away from the pancakes. Immediately cover with the lid and cook for 5 to 6 minutes without peeking, until the bottoms are golden brown and the tops look set around the edges.
Add the remaining tablespoon of water to the pan and slide a wide, thin spatula under one pancake. Support the top with your other hand and flip it over in one smooth motion. Cover again and cook for 4 to 5 minutes until the second side is golden and springy.
Stack two or three pancakes on each plate while still warm and jiggly. Add a pat of butter, drizzle with maple syrup, scatter over fresh berries, and dust with powdered sugar. Serve immediately.