Preheat the oven to 200 ° C. Grease a 12-cavity muffin pan or line it with paper liners.
Sift the flour, baking powder and baking soda into a large bowl and mix in the sugar.
Lightly whisk the egg whites in a mixing bowl or bowl. Stir in the yogurt, sunflower oil and the vanilla flavor. Make a well in the middle of the dry ingredients and pour the liquid ingredients into it. Mix only briefly, do not stir too vigorously.
Pour the dough into the prepared form with a spoon. Bake for about 20 minutes, until the muffins have risen and are golden brown and give slightly at the touch of a finger.
Let the muffins cool in the tin for 5 minutes and serve warm.