Prepare a round cake pan, cover it with cling film and grease the film with neutral vegetable oil.

Leave the butter and cream at room temperature for a few hours. The butter should become soft, which is important for whipping.

Whip the butter well. It should turn white and become creamy. Add heavy cream and continue whipping until the mass becomes fluffy. The butter and cream must be the same temperature and mixed well. After whipping, wash well and wipe dry the mixer beaters so that no fat gets into the egg whites, which need to be whipped next.

Pour sugar and agar into a saucepan, mix well, pour in water and put on medium heat. Stir constantly with a whisk so the agar does not accumulate on the bottom. Cook the same way until the “thin thread” test, or to 110 C (if you have a culinary thermometer). If not, then visually it should noticeably thicken, boil in large bubbles and flow from the whisk in a thin, thick stream. If you are unsure, remember - it is better to overcook in this way than undercook, and let it be thicker than thinner.

While cooking in this way, put the egg whites to beat with a pinch of citric acid until stiff peaks.

As soon as it is ready, continue to beat the egg whites at maximum speed and pour in a thin stream in the same way. Continue beating for at least 5-7 minutes. Then add the mixture of butter and cream and vanilla extract. Beat for another 5-7 minutes. After adding the butter, the mass will fall. Do not be scared; this is how it should be.

Pour the mass into the prepared cake pan and smooth it out well. Leave it in the fridge overnight to harden. Before serving, remove it from the pan and sprinkle with sugar-free cocoa powder. If desired, you can decorate the cake with fruits or berries or pour melted chocolate on top.

Note:

The original recipe uses condensed milk instead of cream, but the editors thought it was too sweet. So we tried replacing the condensed milk with cream, and the result was much tastier. You can also use coconut cream (not milk, cream!).