In a large frying pan melt the butter. Add the apples and fry until tender, 5-10 minutes, over medium to medium-high heat, moving the apples around to be sure they are all coated in the butter and watching them so that they do not burn.
While apples are frying, in a bowl stir together flour, salt and baking powder and spices.
In a separate bowl, whisk together sugar, 2 whole eggs, 1 egg yolk, vanilla extract and lemon zest until creamy and well mixed.
Stir apples with the melted butter into egg and sugar mixture and mix quickly so that the hot butter does not scramble the eggs.
Once apples are covered, add the flour mixture and mix to coat apples.
Spoon into 9" round buttered baking dish.
Bake 30-35 minutes or until cake forms a brown crust on top.
Let cool in pan for 5 minutes.
Invert, then flip back over, apple-side-up, and let cool completely before serving.