Heat the oven to 170°C.
In a bowl mix all the dry ingredients: flour, salt, cocoa, baking powder. Except the sugar.
Separately in another bowl, incorporate the butter together with the sugar until a uniform dough is formed. Add the eggs one by one and the vanilla essence, beat very well.
In another bowl, combine the food coloring with the yogurt and the teaspoon of lemon juice, until a homogeneous mixture is formed.
Pour the mixture into two molds of the same size previously greased and floured.
Bake for approximately 25-30 minutes. Check with a toothpick by poking the center until it comes out dry.
Let the cake cool and then decorate it.
NOTE: use a whisk to mix, you will get a fluffier cake.