Preheat the oven to 180° C. Line a deep rectangular baking pan of approximately 11.80 x 5.10 inches (30cm x 13cm) with parchment paper.
In a medium bowl, sift the flour with the baking powder and salt.
In a large bowl, beat the eggs together with the sugar with an electric mixer or hand whisk for 5 minutes until the mixture lightens in color and turn fluffy.
Carefully add the yogurt, oil, lemon juice, lemon zest and vanilla extract while continuing to beat. Beat for 30 seconds until everything is well integrated.
Add the flour mixture in three separate additions. Beat only for a maximum of 30 seconds after each addition, just until the ingredients are integrated so as not to over beat.
Incorporate the poppy seeds and beat just a little until you get a smooth batter.
Pour the mixture into the mold and bake at 180° C for approximately 45-50 minutes until a wooden toothpick comes out clean when inserted.
Once ready, remove the cake from the oven and let it cool down in the pan for 10 minutes. Then turn it out and let it cool completely on a wire rack.