Separate the whites from the yolks. Put the yolks aside for now, and pour the whites into a large container and beat with a mixer or blender until fluffy and stiff peaks form. Properly beaten whites are white and have a stable structure - they do not spread.
Add yolks and sugar to the whites and mix well.
Take another deep bowl, pour milk into it, add butter and soda. Whisk until the butter dissolves and bubbles appear.
Combine the beaten eggs and milk with the butter. In a separate bowl, mix the flour with the baking powder and carefully, stirring constantly, pour it into the egg-butter mixture.
Add a pinch of salt to the dough and mix again until smooth.
Drain the dates and cut into small cubes.
Place the muffin tins on a baking sheet or in a baking dish and pour the batter into them - about halfway, maybe a little more.
Add chopped dates to the molds with dough and put the muffins in the oven for 25 minutes at 200 °C. Check the readiness with a toothpick: if it comes out dry, then the muffins are ready.