Preheat oven to 425°F.
Cut apple into thin slices and toss slices with brown sugar, cinnamon and lemon juice. Set aside.
Melt butter in a large ovenproof frying pan, wok, or paella pan until the butter is just melted (3-4 minutes..)
In a blender or food processor, blend the eggs, milk and flour at high speed until smooth and well blended. Pour the batter into the pan of melted butter.
Arrange the apple slices in a spoke-like pattern in the center. Bake for 15-20 minutes or until puffed and golden brown. Serve immediately with maple syrup.