Step 1Heat the oven to 350 degrees. Lightly grease the bottom and sides of a large Dutch oven or other ovenproof pot with a lid.
Step 2Heat the oil in a large skillet over medium heat. Add the apples and cook, stirring occasionally, until slightly softened, about 5 minutes. Add the white wine, increase the heat to medium-high and cook, uncovered and stirring occasionally, until most of the liquid has evaporated and the apples are very tender, 5 to 7 minutes. Remove from the heat and let cool slightly.
Step 3Meanwhile, whisk together the eggs, sugar, vanilla and salt in a large bowl. In another bowl, combine the challah with enough water to cover. Let sit for a few seconds, then drain and squeeze dry. Add the bread to the egg mixture and stir to combine, then fold in the raisins.
Step 4Fold in the cooled apples and transfer the mixture to the prepared Dutch oven. Cover and bake until it is puffed and golden brown, 1 to 1½ hours. Set the Dutch oven on a wire rack to cool for 20 minutes before serving.