Position an oven rack in the center and preheat the oven to 350F degrees. Lightly mist an 8 x 8-inch square baking pan with nonstick cooking spray and set it aside.
To make the streusel, in a small bow, stir together the brown sugar, cinnamon and pecans until well combined.
To make the cake, in a large bowl, beat together the dry cake mix, flour, yogurt, water, oil, egg and vanilla with an electric mixer on medium until smooth, 1 to 2 minutes.
Scrape ½ the batter into the prepared pan and smooth it out evenly. Sprinkle ½ the streusel mixture evenly over the batter in the pan.
Scrape the remaining batter over the topping, spreading it out evenly. Sprinkle the rest of the streusel topping over the cake batter.
Bake until golden brown and a toothpick inserted in the center comes out clean, 25 to 30 minutes.
Remove from the oven and place on a wire rack to cool for 20 minutes.
Slice and serve while still a little warm.
Recipe Notes
Click here to see your WW PersonalPoints for this recipe and track it in the WW app or site.5*SmartPoints (Green plan)5*SmartPoints (Blue plan)5*SmartPoints (Purple plan)4*PointsPlus (Old plan)