Preheat oven to 375ºF. Spray pan with vegetable pan spray.
For streusel, combine all ingredients in small bowl; mix until mixture resembles coarse crumbs.
In medium bowl, combine flour, sugars, baking powder and salt; mix well. In large bowl, beat eggs with milk, oil and vanilla; add flour mixture and stir just until dry ingredients are moistened. (Do not overmix.) Gently stir in nuts and apples. Fill pan cavities 2/3 full; sprinkle with streusel topping.
Bake 10-12 minutes or until light golden brown. Cool 3-4 minutes before removing from pan. Serve warm or at room temperature.