1. Preheat oven to 350 degrees. Butter and flour a 5-by-9-inch loaf pan. Whisk together flour, baking powder, cinnamon, and salt. Mix together oil and sugar with a mixer on medium speed until combined. With machine running, add eggs, 1 at a time. Reduce speed to low, and beat in flour mixture in 3 additions, alternating with 1/2 cup cider and the brandy (if not using brandy, use an additional 1/4 cup cider), beginning and ending with flour. Add vanilla, and fold in apples. Pour mixture into pan, and top with oatmeal-walnut crumble.

2. Place pan on a rimmed baking sheet, and bake until a tester inserted into center comes out clean, 45 to 55 minutes. Transfer pan to a wire rack, and let cool for 15 minutes. Invert pan to remove bread. Let cool completely on a wire rack, crumble side up. Drizzle with caramel sauce just before serving.