Step 1

Preheat the oven to 375°. In a 10 1/2-inch nonstick ovenproof skillet, melt the butter. Add the apples, 1 tablespoon of the sugar and the lemon juice and cook over moderately high heat, stirring occasionally, until the apples are golden, about 6 minutes. Add the 1/4 cup of maple syrup and simmer over low heat until thickened, about 1 minute. Spread the apples in an even layer and remove the pan from the heat.

Step 2

In a medium bowl, whisk the flour with the baking powder and salt. In a measuring cup, whisk the egg yolks with the milk and the remaining 2 tablespoons of sugar. Whisk the liquid into the dry ingredients.

Step 3

In a medium bowl, using a handheld electric mixer, beat the egg whites at medium speed until firm peaks form, about 2 minutes. Fold the beaten whites into the batter and scrape it over the apples; spread the batter to the edge.

Step 4

Bake the pancake in the upper third of the oven for about 20 minutes, until it is golden, puffed and set. Let the pancake cool for 5 minutes. Run a knife around the edge to loosen the pancake, then invert it onto a serving plate. Replace any apples that may have stuck to the pan. Cut the pancake into wedges and serve at once with the warmed maple syrup.