1. In a large bowl, vigorously beat the eggs + sugar until the mixture acquires a whitish color. Add the natural yogurt and mix. Add the dry ingredients (flour + chemical booster) to the preparation and mix. Add the melted butter.
2. Divide the dough into two different bowls. In one of them, add the cocoa powder and mix well.
3. In the other bowl, add the vanilla and mix well.
4. With the help of some soup spoons, pour the two masses into the muffin mold, alternating them randomly.
5. When we have put all the dough in the mold, with a wooden skewer or the tip of a knife, mix both masses a little, without mixing excessively so that it does not collapse.
6. In an oven preheated to 180°C, we will cook our muffins for 15 minutes.
7. Once baked, let them cool completely (preferably on a rack).
