Ingredients
2  tart apples, peeled, cored, thinly sliced 
3  tablespoons sugar 
1  lemon, juice of 
1/4  teaspoon ground cinnamon 
6  tablespoons unsalted butter 
3  eggs 
3/4  cup milk 
3/4  cup flour 
1/2  teaspoon salt 
 confectioners' sugar

Directions 
Combine apples, sugar, 2 T of the lemon juice and cinnamon in a medium bowl; toss to coat apples. Melt 2 T of the butter in a skillet over medium-high heat; add apples, cook just until soft, 3 minutes; remove from heat and set aside.
 
Heat oven to 450 degrees. Whisk together eggs and milk in a bowl until well blended, whisk in flour and salt to form a slightly lumpy batter. Melt remaining 4 T of the butter in an oven-proof 10-inch skillet (a well-seasoned cast iron skillet is good) until just beginning to brown, about 2 minutes; spread apples in bottom of pan, pour batter over apples. 

Bake until the pancake is golden brown and puffed, about 20 minutes; invert onto a large platter. Sprinkle with remaining lemon juice; dust with confectioners' sugar.
 
Source:  Chef Thorsten  Bonn, Germany