Heat oven to 350 degrees F. Coat a 10-inch tube pan with nonstick cooking spray.
Combine pecans, brown sugar and cinnamon in small bowl. Set aside.
In a large bowl, whisk together flour, baking powder, baking soda and salt.
In a second large bowl, beat butter and Splenda on medium speed until fluffy. Add eggs and egg whites, one at a time, beating well after each addition. Beat in vanilla.
Reduce speed to low and alternately beat in flour mixture and yogurt, beginning and ending with flour mixture.
Spread half of the batter into prepared pan and sprinkle evenly with half of pecan mixture. Carefully spread remaining batter over top and sprinkle with remaining pecan mixture.
Bake at 350 degrees F. for 50 to 55 minutes or until a toothpick inserted in cake comes out clean. Cool on a wire rack for 20 minutes. Gently remove side from pan. Run a small sharp knife around bottom and center and cool completely before removing from pan.
