Preparation:
1. Preheat the oven to 180°C (350°F).
2. Make a mold for cupcakes or buttercream and place the paper lids (if you have them).
3. In a large bowl, beat the butter and sugar until you get a smooth and creamy mixture.
4. Add the eggs one by one, making sure to mix well after each addition.
5. Add vanilla and the zest of lemon or orange, if you choose to use, for a citrusy touch.
6. Sift flour together with baking powder.
7. Add this flour mixture little by little to the egg and butter mixture, alternating with milk. Beat until everything is well integrated, but don’t over beat so that the butter is fluffy.
8. Pour the dough into the caps or molds, filling them about 2/3 of their capacity to leave room for them to climb.
9. Bake in the preheated oven for 20-25 minutes, or until buttered is golden brown and inserting a chopstick in the center comes out clean.
10. Remove butter from oven and let cool on a griddle.
