In a bowl crack eggs, add sugar, vanilla sugar, salt.

Whisk until the weight increase twice. In kefir put soda and mix well. Yogurt should foam. So soda to extinguish.

Add yogurt to egg mixture and whisk for 15-20 seconds.

Then add the softened butter, vegetable oil, flour. Whisk until smooth. At the end pour in the batter cranberries and stir gently.

The dough is poured into molds, it is very desirable in paper inserts.. the Dough will be very delicate and airy. As a form of no lubricate, will still stick to the wall. Therefore it is better to use paper inserts. Put in a preheated 180 degree oven. I baked the muffins for 50 minutes. Baking time depends on the power of your oven. Check the match readiness. The match should come out moist but without a test.

Muffins better to cool directly in the forms. They are very delicate. Before removing the paper base, wait until they completely cooled.

They have an amazing crispy crust... but inside they are gentle and airy. You can sprinkle them with powdered sugar. Better yet, put a scoop of ice cream and enjoy the stunning combination of flavors! Cranberries gives a light acidity. Sugar can be put less than the recipe, what I actually did. Because I do not like much sweet. Be guided by your taste.