1Preheat oven to 350ºF. Line a 12-cup muffin tin; set aside. Whisk flour, cocoa, baking powder and salt in a bowl; set aside.
2In a separate bowl, whisk eggs, sugar and olive oil, until thick and well-mixed. Whisk in the vanilla extract. Add the flour mixture and pour in the milk, stirring well with a wooden spoon until just combined. Spoon batter into prepared muffin cups, filling 2/3 of the way. Bake for 18 to 20 minutes, until center springs back when gently touched or a metal skewer inserted comes out clean.
3Remove from oven and set on a wire rack to cool completely. If desired, sift powdered sugar over tops before serving.