For the cupcakes, mix all the dry ingredients in a large bowl then add the eggs, vanilla extract, butter, and milk and mix with a whisk until you get a homogeneous dough.
Prepare a cupcake tray with paper liners, and put a large spoonful of dough in each mold.
Bake in the oven at 180 °C (356 °F).
Frosting
Mix all the ingredients in a saucepan with a whisk and cook over low heat, stirring constantly to avoid sticking until the frosting thickens.
Place the frosting in a bowl and leave in the refrigerator to cool. Before using it, blend it in a blender until you get a smooth cream that you put in a piping bag to use to decorate the cupcakes.