Adjust oven rack to upper-middle position and heat oven to 500 degrees.
Whisk flour and granulated sugar together in large bowl.In small bowl,whisk milk,eggs and vanilla together.Whisk the milk mixture into the flour mixture until smooth with no lumps.
Melt the butter in a 10 inch ovenproof nonstick skillet over medium-high heat.Add the apples,brown sugar and cinnamon and cook,stirring often,until apples are golden brown,about 10 minutes.Off the heat,stir in lemon juice.
Quickly pour the batter around the edge of the skillet,then over the apples.Place the skillet in oven and immediately reduce oven to 425 degrees.Bake until the pancake is brown and has risen above the edges of the skillet,about 18 minutes.
Loosen the pancake edges from the hot skillet with a spatula and flip the pancake onto a large plate.Dust with icing sugar if desired.Cut into wedges and serve.