Preheat oven to 200 degrees.

Preheat a Belgian waffle iron.

In a medium bowl, sift together flour, sugar, baking powder, and baking soda.

In a separate medium bowl, whisk together sour cream, egg yolks, margarine, and vanilla extract.

Pour the wet ingredients into the dry ingredients and stir to form a lumpy batter.

In another medium bowl, beat egg whites until stiff peaks form.

Gently fold the beaten egg whites into the batter until just combined, being careful not to overmix.

Lightly spray the preheated waffle iron with cooking spray.

Spoon about 1/3 cup of batter onto the hot waffle iron, spreading it evenly.

Close the lid and bake until the waffle is golden brown and crisp, about 2 minutes.

Transfer the baked waffle to the preheated oven to keep warm and crisp.

Repeat with the remaining batter.

Serve hot with desired toppings such as fruit, syrup, or whipped cream.