Combine the flour, baking powder and salt, set aside. In a large bowl, mix sugar, oil and vanilla. Add the eggs and mix until well blended. Add half the flour mixture and mix well. Stir in apples, nuts and milk. Add the remaining flour mixture and mix just until blended. Grease the bottoms of twelve 2 1/2 inch muffin cups and divide the batter among the cups. Bake in a preheated oven at 350ºF. for 25 minutes, or until a toothpick inserted in the center, comes out clean and the muffins are golden brown. Remove from the cups and serve warm.