Red fruit cupcakes

I have been baking forever, but it is only last week that I have discovered the ultimate secret to perfect cake! I was baking vanilla cupcakes and mixed the butter unusually long since I was busy doing other stuff, then I added the sugar, and again, mixed the butter and sugar unusually long (for about 7 minutes). By then, the mixture was so fluffy and white, as it had never been before!

Encouraged by that, I proceeded as usual. The result was great: fluffy, light cupcakes! I then tried it again next time when I prepared these cupcakes with red fruits. Here is the recipe: beat 250g warm butter, nearly melted, for 5 minutes. When very fluffy and white, add 200g sugar and beat for another 7 minutes. Then, add 4 eggs, one by one, always beating 1 minute before adding the next egg. Add 250g flour mixed with 2 teaspoons baking powder in two times, adding a tablespoon or 2 of milk in between. Prepare 18 cupcake tins.  Place one tablespoon of batter in each of the cupcake tins. Then, gently put a teaspoon of mixed red fruits in the middle of each cupcake (I took frozen ones, defrosted, but fresh should be even better, since there will be no excess juice so that the cupcakes will keep better their airiness), cover with another tablespoon of batter. Put in the preheated oven (180 degrees) for 20 minutes. Leave in the oven to cool. Enjoy!