Greek Stuffed Zucchini with Ground Beef (Yemista me Avgolemono)

Steps

1. Slice off the tops and bottoms of the zucchini, then cut each in half crosswise. Hollow out each piece with an apple corer, keeping the walls intact.
2. In a bowl, combine the ground beef, spring onions, red onion, rice, parsley, dill, ground fennel, and 100 ml olive oil. Season with salt and pepper and mix well.
3. Stuff each hollowed zucchini piece with the meat and rice filling, packing it in firmly.
4. Arrange the stuffed zucchini upright in a large pot. Pour in the stock (or water) until it comes about halfway up the zucchini.
5. Cover and simmer over medium-low heat for about 45-60 minutes, until the zucchini are tender and the rice inside is fully cooked.
6. Remove the pot from the heat. Ladle out about 1-2 cups of the hot cooking liquid and set aside to cool slightly.
7. In a bowl, whisk the flour with the 6 tablespoons olive oil to form a smooth paste. Whisk in the eggs, egg yolk, lemon juice, and lemon zest until combined.
8. Slowly whisk the reserved hot liquid into the egg mixture to temper it, then pour the tempered mixture back into the pot with the zucchini.
9. Gently shake the pot or stir carefully over low heat until the sauce thickens slightly; do not let it boil.
10. Serve the stuffed zucchini warm, topped with the avgolemono sauce and freshly ground pepper.