Wash the zucchinis well, cut off the tops, and using a spoon scoop out the inside flesh. Place the flesh in a bowl.
On a cutting board, finely chop the onion and garlic with a sharp knife, and grate the carrot using the coarse side of a grater.
Using the same cutting board, cut the chicken thigh fillets into very small bite-sized pieces.
Place a large non-stick frying pan over high heat and let it get hot. Add the olive oil.
Sauté the onion, garlic, carrot, and chicken pieces until nicely browned, seasoning with salt and freshly ground pepper.
Add the rice and lemon zest. Deglaze with the white wine and, once the alcohol has evaporated, add the chicken stock. Lower the heat and let the chicken and rice simmer for 12–14 minutes, until almost all the stock has been absorbed.
Remove the pan from the heat, add the parsley and dill, and allow the mixture to cool.
Season the inside of the zucchinis with salt and freshly ground pepper, then fill them with the mixture.
Place the stuffed zucchinis in a pot and add the wedge-cut potatoes in between them.
Add water until it reaches slightly above the middle of the zucchinis. Season with salt and freshly ground pepper, cover the pot, and simmer over medium heat for about 25 minutes, until the potatoes and rice are fully cooked.
In a bowl, whisk together the egg yolks, lemon juice, and corn flour until smooth.
Slowly add some of the hot broth from the pot while whisking continuously so the eggs do not curdle.
Once the egg mixture has reached a similar temperature to the broth in the pot, pour it back into the pot. Gently shake and stir the pot carefully to combine, then serve.
