Preheat the oven to 350 and grease a 9-inch springform pan (cake will rise so make sure that you are using a tall pan not a short cake pan) OR you can use a 9x13 casserole baking pan but watch the bake time.
Peel core and dice the apples. Set aside.
If using a stand-up electric mixer, use whisk attachment. Beat eggs and sugar on high, for a 2-3 of minutes, until light-yellow, thickened and about triple in size.
Lower the speed to low and beat in vanilla and flour. Quickly mix baking soda and vinegar and add it to the batter.
Mix batter and apples and add it to the cake pan. Bake for 55-60 minutes (if using 9x13 pan, bake time will be 20-25 minutes).