Place prunes and water in a saucepan. Cook on medium heat until soft. This takes about 8 minutes. Let them cool slightly, then mash into a thick puree.

Preheat your oven to 180°C (350°F). Grease an 8x8 baking dish lightly. You can also line it with parchment paper for easy removal after baking.

In a bowl, add flour, baking soda, salt, cinnamon and nutmeg. Mix well using a spoon. This helps distribute spices evenly in the cake batter.

In another bowl, beat eggs and sugar until light and creamy. This step helps create a soft texture. Use a whisk or mixer for best results.

Add oil, vanilla extract and buttermilk to the egg mixture. Mix well until smooth. This gives moisture and richness to the cake batter.

Add the mashed prunes into the wet mixture. Then slowly add dry ingredients. Mix gently until smooth. Do not overmix to keep the cake soft.

Pour the batter into the prepared baking dish. Bake for 30 to 35 minutes. Insert a toothpick in the center. If it comes out clean, the cake is ready.

Remove from oven and let the cake cool on a rack. Slice into squares and serve. Enjoy warm or at room temperature with your favorite drink.