First thing, turn the oven on to preheat.
Separate the whites from the yolks and whip the whites in a grease-free bowl until curdled.
Add sugar to the whites 1 tbsp at a time and whip into a thick foam, then fold in the yolks in parts, continuing to whip.
Turn off the mixer, sift in the flour, add the poppy seeds and stir in the essence. Gently and quickly fold with a spatula and pour the batter into the pan.
Bake 30-35 minutes at 160 °C until a skewer comes out dry.
Let the finished sponge cool, or better yet, leave it overnight to mature and rest.