Soak the dates in one cup of milk overnight in the fridge (at least 12 hours)
Dates puree
With a food processor or a blender, puree the dates with only 40 g of the milk used for soaking, to get a date paste.
Mixing
Whisk the date paste with room temperature butter, sugar and salt. Whisk until everything is well combined. It is important that your butter is room temperature here otherwise it will be very difficult to mix everything together.
Add orange blossom water and zest of 2 lemons before whisking with eggs.
Add the flour and baking powder sifted and whisk.
Baking
Baking time will really depend on your oven. I bake for 50 min at 160C (320F). The best way to know if your cake is ready is to poke it in the center with a knife or a toothpick. You should stop as soon as the knife comes back dry. Any more than that, and it will get dry.