Melt the butter in a skillet over medium heat. Add the brown sugar, cinnamon, and salt, stirring until the sugar begins to dissolve. Add the banana slices and cook for 1–2 minutes per side, until glossy, lightly browned, and just softened. Stir in the vanilla if using, then remove from the heat and keep warm.

Whisk the egg yolks with the milk and vanilla. Sift in the flour, baking powder, and salt, then whisk only until smooth. Do not overmix the batter.

Beat the egg whites until foamy. Add the cream of tartar, then gradually beat in the sugar until the meringue forms glossy medium-stiff or stiff peaks that hold their shape without appearing dry.

Fold one-third of the meringue into the yolk batter to lighten it. Gently fold in the remaining meringue in two additions, stopping as soon as no large white streaks remain.

Lightly grease a nonstick skillet and heat it over very low heat. Spoon or pipe the batter into tall rounds, using ring molds if desired. Add 1–2 teaspoons of water to the empty part of the pan, keeping it away from the batter, and cover with a lid.

Cook for approximately 4–6 minutes, until the bottoms are golden and the pancakes are set enough to lift. For especially tall pancakes, add another small spoonful of batter to the top halfway through cooking.

Carefully turn each pancake, cover the skillet again, and cook for another 3–5 minutes. The pancakes should feel springy and be cooked through in the center. Serve immediately with the warm caramelized bananas, powdered sugar, and any optional syrup or whipped cream.