Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, baking powder, and salt in a medium bowl, stirring with a whisk.
Place sugar, vanilla, and eggs in a large bowl; beat with a mixer at medium speed for 3 minutes or until thick. With mixer on low speed, gradually add flour mixture. Gently fold in apple mixture and pecans. Spoon batter into an 8-inch square baking pan coated with cooking spray. Bake at 350º for 25 minutes or until top is puffed and deep golden brown. Serve warm.