Boil enough water in a large saucepan and then add the eggplants. Boil for 5-10 minutes until the eggplants are softened
Once they have softened, turn off the heat and let them rest in the water for 10-15 minutes. Then drain them.
Cut the tops of the eggplants. Then carefully slice half-way through, lengthwise - like a book.
Rub some salt on the inside of each eggplant then arrange them on a flat surface, not touching each other and press them with a heavy object. You could use a big pan lid or the bottom of a flat dish to place on top of them, then add another heavy object on top. Alternatively, you could arrange them within a colander and press with a heavy object.
With the combination of pressing and salt, this should help remove all the excess water from the eggplant. Keep them pressed for a few hours or even overnight to get as much of the water out as possible. The key is to keep them in a cool area, and this process can take up to 24 hours, do be patient and check them after every 5-6 hours. See video.
When you are ready to proceed, first make the stuffing. Slice the peppers and remove all seeds. Then either finely chop them or blitz them in a food processor/blender for a bit.
Next, strain the liquid from the crushed peppers. You can put them in a sieve and press out all the excess liquid.**
Mash or grind the garlic cloves and roughly chop the walnuts. If you prefer, you can grind the walnuts into even smaller pieces. Then, mix the peppers, nuts and garlic together.
Stuff the eggplant shells with about 1 tablespoon of the pepper walnut mixture. Depending on the size of the eggplants, adjust the amount.
For the next step, use a sterilised clean glass jar. To sterilise the jar, simply wash it with hot water, then put it in the oven (no rubber parts) for 10 minutes at 160ºC. Or after washing, pour boiling hot water over the jar ( just make sure it's heat-safe!
Arrange the stuffed eggplants in the jar. Stack them carefully so that the stuffing doesn't fall out
Sprinkle liberally with salt on top then fill the jar with olive oil. Make sure all the eggplants are entirely covered and tightly close the jar. **
Store your jar in a cool, dark place such as a kitchen cupboard. The pickled eggplants - Makdous - will be ready in about 10-14 days ( although some people find they're ready at seven). If at any point you notice that the olive oil isn't entirely covering the eggplants, add more olive oil.
If you keep them in the oil, completely covered, the Makdous can keep for up to a year. No need to refrigerate, just keep at room temperature in your cupboard as the olive oil acts as a natural preserver.
* If you don't press all the water out of the eggplants then they can be 'sour' tasting, which isn't what you want.
** The drained pepper liquid can be used in making tomato sauces or dips or pasta sauces.
***To help the olive oil penetrate all the way into the jar, you can use a spoon or knife to lodge down into the sides of the jar and 'wiggle' it, to allow the olive oil to get everywhere.
Note: After the eggplants are consumed, you can still re-use the oil - it gets infused with the aromas of the eggplants and the stuffing.