If you have a blender, blend the eggs, milk and flour on high speed until smooth, light and fluffy. If you don't have a blender, beat these ingredients well with a mixer. You want to incorporate some air into the batter.
Melt the butter in the skillet on the stove-top. Scatter the sliced apples into the skillet and sprinkle them with some ground cinnamon and sugar to your taste. We like to leave the peels on the apple for added texture. Lightly saute the apples for just a minute or so.
Gently pour the batter into the skillet and pop it into the oven. Bake about 20 minutes at 400 degrees F until it has puffed up and is golden.
Remove from oven and invert onto a plate. Sprinkle with lots of powdered sugar and squeeze some lemon wedges over the top. Cut into 4 pieces and serve with remaining lemon wedges.
Note* You can use a mixture of tart red and green apples and leave the skin on - adds some nice color. Try this with fresh peaches in season.