Preparation Preheat oven to 350°F. Spray 12-cup Bundt pan with nonstick spray. Sift flour, cinnamon, baking soda, and salt into medium bowl. Transfer 3 tablespoons flour mixture to Bundt pan and tilt to coat. Set pan aside. Place apples and 2 tablespoons flour mixture in another medium bowl; toss to coat apples. Combine 1 cup brown sugar, vegetable oil, 1 cup sugar, eggs, and 3 teaspoons vanilla in large bowl. Using electric mixer, beat until mixture is thick, about 4 minutes. Gradually beat in remaining flour mixture. Fold apple mixture and pecans into batter; transfer to prepared Bundt pan. Bake cake until tester inserted near center comes out clean, about 1 hour. Transfer cake in pan to rack. Let stand while making caramel. Melt butter in heavy small skillet over medium heat. Whisk in remaining 1 cup brown sugar, then milk. Continue to whisk until topping is smooth and blended and comes to boil, about 5 minutes. Whisk in remaining 1 teaspoon vanilla. Spoon 1/4 cup hot caramel topping over warm cake in pan. Let stand until topping is absorbed into cake, about 15 minutes. Turn cake out onto platter. Pour remaining warm topping over cake. Let stand until cool, at least 1 hour. (Can be made 1 day ahead. Cover with cake dome. Let stand at room temperature.)
Preparation Preheat oven to 350°F. Spray 12-cup Bundt pan with nonstick spray. Sift flour, cinnamon, baking soda, and salt into medium bowl. Transfer 3 tablespoons flour mixture to Bundt pan and tilt to coat. Set pan aside. Place apples and 2 tablespoons flour mixture in another medium bowl; toss to coat apples. Combine 1 cup brown sugar, vegetable oil, 1 cup sugar, eggs, and 3 teaspoons vanilla in large bowl. Using electric mixer, beat until mixture is thick, about 4 minutes. Gradually beat in remaining flour mixture. Fold apple mixture and pecans into batter; transfer to prepared Bundt pan. Bake cake until tester inserted near center comes out clean, about 1 hour. Transfer cake in pan to rack. Let stand while making caramel. Melt butter in heavy small skillet over medium heat. Whisk in remaining 1 cup brown sugar, then milk. Continue to whisk until topping is smooth and blended and comes to boil, about 5 minutes. Whisk in remaining 1 teaspoon vanilla. Spoon 1/4 cup hot caramel topping over warm cake in pan. Let stand until topping is absorbed into cake, about 15 minutes. Turn cake out onto platter. Pour remaining warm topping over cake. Let stand until cool, at least 1 hour. (Can be made 1 day ahead. Cover with cake dome. Let stand at room temperature.)