Preheat oven to 350°F. Coat bundt pan with non-stick spray. Using a electric mixer, beat butter, sugar, and vanilla in large bowl to blend. Add egg yolks one at a time, beating to blend after each addition.
Whisk flour, salt, and baking soda in medium bowl to combine. Add one-third of dry ingredients to butter mixture, beating to blend. Add half of sour cream and beat to blend. Repeat altering of dry ingredients and sour cream ending with dry flour mixture.
Using electric mixer fitted with clean dry beaters, beat egg whites to stiff peaks. Fold one third of beaten egg whites into cake batter to lighten. Add the remaining egg whites to batter till fully incorporated. Spoon batter into prepared pan.
Bake till top of cake is golden and cracked and center is set, about 25 minutes. Transfer to cooling rack and let stand 15 minutes. Using a small, sharp knife cut around sides of pan to loosen and invert cake onto rack. Cool completely. Serve with fresh fruit or Cool Whip whipped topping or vanilla ice cream.