Over medium heat, melt the 2 tablespoons of butter in a shallow frying pan. Once the butter begins to sizzle, add in the brown sugar & ground cinnamon and allow the sugar to begin to melt for a minute or so, stirring constantly. Add the apples, and saute, stirring from time to time. until the apples are tender but not collapsing. Remove from the pan and set aside.
Return the pan to the heat & add a generous spoonful of butter to the dish.
While the apples are sauteing,lightly beat the eggs in a large shallow dish. Add in the milk, cinnamon & vanilla. Gently dip the sliced bread in the egg bath, being sure to turn the bread to coat both sides. If you are using thicker bread, you can let the bread soak in the egg bath while you cook the apples.
Once the butter has melted, add the soaked bread to the frying pan & cook until deep golden on one side, flip & repeat on the other side of bread.
Place the french toast on a plate & then top with caramelized apples. Serve immediately