We grease a removable base mold of 20 cm diameter and high walls with a little butter. We sprinkle with flour and shake it so that it spreads well over the base and the walls. We turn the mold over the pile and let the excess flour fall.
Heat the milk, butter and vanilla essence in a saucepan. Before it starts to boil, we turn off the fire and we let temper couple of minutes. Meanwhile, in a deep and wide bowl, beat the eggs and sugar with an electric whisk until the mixture is creamy and whitish.
Add the hot milk mixture to the container with the egg, little by little and without stopping stirring with the rods. Next, we add the flour and the baking powder, sifted, and stir gently until incorporated, just enough so that the entire dough is integrated.
Pour the dough into the mold. We lift it an inch and tap it gently against the counter. We repeat this process again. This little gesture remove the bubbles of air and the crumb is more homogeneous.
We put the mold in the oven, preheated to 180 ºC with heat up and down, and cook the cake for 40 minutes. Then we turn off the oven and let it finish cooking with the residual heat for a further 10-15 minutes. We remove and, once cold, we unmold and ready to enjoy.