Preheat the oven to 180 degrees Celsius.
Separate the egg white from the yolks.
Mix the yolks with half of the sugar until you obtain a cream.
Add the oil step by step, and mix well to incorporate it.
Add the yogurt and the vanilla essence to the mix.
Mix the flour with the baking powder, and add it to the wet mix. Combine all together until you have a smooth batter.
In a separate bowl whisk the egg whites with a little bit of salt until they become fluffy. Add the sugar and whisk until the composition becomes stiff. Don’t over whisk.
Fold the egg whites into the batter, gently, to avoid removing the air.
Fold in the blackberries, gently, reserving a few for decorating the final cake.
Prepare a loaf pan by layering it with baking paper.
Add the batter in the tray, and decorate with the last remaining blackberries.
Bake for 40 minutes, until the loaf cake becomes golden brown. Test to see if it’s done by inserting a toothpick inside it. If it comes out clean, it is ready. My oven is a bit older and doesn’t cook evenly, so it took around 50 minutes for this blackberry loaf cake to fully cook.
Let the blackberry loaf cake cool down completely inside the tray, before taking it out and cutting it.
Enjoy with coffee, tea, or as an afternoon snack.