Prepare the whipped cream by placing a bowl over an ice bath. Whisk heavy cream and sugar until medium-firm peaks form. Chill until ready to serve.
Separate egg yolks and whites into different bowls. Freeze egg whites for 15 minutes.
Mix egg yolks with milk and vanilla extract until pale and frothy.
Sift cake flour and baking powder into the yolk mixture and whisk gently until combined.
Heat a nonstick pan to 300°F (150°C) over very low heat.
Beat chilled egg whites until foamy, then gradually add sugar and continue beating until stiff glossy peaks form.
Fold one-third of the meringue into the yolk mixture to lighten it. Gently fold in the remaining meringue until combined without deflating the batter.
Lightly grease the pan with oil and wipe away excess.
Scoop tall mounds of batter into the pan to form 3 pancakes. Add additional scoops to build height.
Add water to the pan, cover, and steam-cook for 6–7 minutes. Add a final scoop of batter after 2 minutes if desired.
Carefully flip each pancake using a gentle rolling motion. Add more water, cover, and cook for another 4–5 minutes until golden and set.
Transfer pancakes to plates and top with whipped cream, berries, powdered sugar, and maple syrup. Serve immediately.