Heat oven to 350ºF with rack in center of oven. Coat a 9" bundt pan with cooking spray then dust lightly with flour.
In a medium bowl, combine by whisking the flours, baking powder, baking soda, salt, Splenda and almonds.
In another bowl, whip the egg whites until foamy then add the cream of tartar. Beat until soft peaks form then add the sugar. Continue beating until stiff peaks form. Set aside.
In yet another bowl, a large one this time, combine the oil, egg substitute, yogurt, vanilla, orange zest and juice. Gently stir in the flour mixture. Stir a spoonful of the whipped egg whites into the batter to lighten then fold in the remaining.
Pour into prepared pan and bake for 25 minutes or until cake is springy to the touch and a toothpick inserted in the center comes out clean.
Cool in pan for 10 minutes before depanning & cooling completely on a rack.