Preheat the oven to 356º F (180° C). Grease and line a round cake pan or a bundt cake pan of about 9 inches (23 cm) with parchment paper.
In a medium bowl, sift together the flour, baking powder, baking soda and salt.
In a large bowl, beat together the eggs and sugar using an electric mixer or hand whisk for 2 minutes until light and fluffy.
Beat in the olive oil with the milk and the lemon/orange zest and beat for 1 more minute until everything is well integrated.
Add the flour mixture in two separate additions, beating for 20 seconds after each addition to get a smooth batter.
Pour the mixture into the pan and spread it with a rubber spatula to even it out. Bake at 356º F (180° C) for 45 minutes to 1 hour approximately until a wooden toothpick comes out clean chen inserted.
Once the cake is ready, take it out of the oven, let it rest for 10 minutes before turning it out and then place it on a rack to cool down for at least another 10 minutes.
Decorate the cake with powdered sugar and sliced almonds if desired.