Chop the zucchini coarsely in a food processor. Add the finely chopped garlic. Add the eggs and yoghurt (to which you've added the baking soda beforehand). Season. Next, add the flour and stir well.
If the zucchini have a higher water content and the mixture doesn't seem thick enough (it needs to be like a cake dough), then add a little more flour. Put baking paper in a rectangular tray, smear it well with oil. Spread the zucchini mixture out in a thin layer.
Bake at about 356°F (180 °C) with the fan on for 25 min. or until it becomes a golden brown. While still hot, roll up the layer and put it aside to cool.
Unroll the layer and smear ti generously with the creamy mixture. Arrange the capers at one end and roll it back up.
Store in the fridge and serve it cut into round slices and well cooled.