Halve the zucchini lengthways and carve out the pulp with a spoon or scoop. Sprinkle carved zucchini halves with salt and set aside.
Warm the oil in a frying pan, mince the shallots and add to the pan. Meanwhile, mince the zucchini pulp and add to softened onion. Sauté for 4-5 minutes, then remove from the heat.
Drain the tuna and crush it with a fork. Crumble the feta and add it to the tuna. Combine onion and zucchini pulp mixture and give a stir. Crack in the egg and stir to combine. Lastly, stir in 30 g of breadcrumbs, saving 10 g aside. Taste test and add salt if needed.
Divide mixture between the 4 zucchini halves, then sprinkle the top with remaining breadcrumbs and black pepper. Bake at 200°C (392°F) for 20 minutes. Serve warm.
Notes
You can either use tuna in oil or in brine. I tend to prefer tuna in oil, as I find it more flavourful. Regardless, properly drain the tuna before adding it to the stuffing mixture.Nutritional information is just an estimate based on a suggested serving size.