Rainbow Cupcakes

Materials:For cupcakes (about 12)200 gr. butter at room temperature50 ml sunflower150g. yogurt350 gr. white sugar2 tsp vanilla extract4 eggs475 gr. flour, all-purpose3 tbsp baking powdervarious colors confectioneryFor the topping:5 egg whites1; cups white sugar1 ½ cups of butter at room temperature and cut into cubes
Execution:
Preheat oven to 180 C. In a bowl, beat at medium speed sunflower oil with sugar, butter and yogurt until homogeneous and produce a thick mixture. Add eggs one at a time and vanilla and mix again. Sieve the mixture into the flour and baking powder and mix at low speed for 2-3 minutes. Divide the dough in bowl so what colors we want to have cupcakes.
Add the colors we each bowl, little bit until the desired result, stirring until the mixture is uniformly colored.In a fit place for cupcakes paper cases. Into receptacles place one tablespoon of each color to fill in 2/3. Bake for 25 minutes until cooked long enough dipping a toothpick comes out clean. Remove from the oven and allow to cool.For coating put on a pot egg whites and sugar. Place the pot in a larger boiling water (bain marie) and stir constantly until the sugar is completely melted. I'll understand if tasting a little mix at our fingertips, we do not feel any grains of sugar and the mixture is a little more than lukewarm. Pour the mixture into a bowl and stir in gradually increasing speed until a stiff meringue and cool completely, about 8-10 minutes. Reduce speed and gradually add the butter. The mixture will become more fluid and will start breaking. Continue stirring until it thickens and is smooth and uniform. Although still very fluid put in the fridge for 15 minutes and then continue stirring. Place the mixture into a pastry piping bag and decorate the cupcakes.