Wash and empty the zucchinis without breaking the edges
Prepare the stuffing, by rinsing well the rice and soaking it for 10 minutes, strain well and mix it to the ground meat, add the spices and a dollop of vegetable oil. Add salt and set aside
Preapre the cooked yogurt, by dissolving the corn flour in the 1/2 cup of water or by directly adding the corn flour to the yogurt while being sure it all dissolved before cooking it.
In a big cooking pot, add the yogurt and give it a stir until smooth, add the corn flour mixture at this point or just the corn flour and stir. heat on, cook the yogurt on low heat while continiously stirring clockwise. You will notice the yogurt will get ticker and at the first boil, turn off the heat. Add salt and reserve.
Stuff the zucchinis, cover them in water in a pot. Add salt and the garlic cloves. Cook on medium heat until the zucchinis are just al dente. Remove from the pot and bring the vegetable broth for 10 minutes.
Drop carefully the zucchinis to the ceamy yogurt, the remaining vegtable broth and the cooked garlic cloves. Heat on, bring into a simmer or until the rice inside the zucchini is really soft. Check the seasoning, add salt if it is needed. Sprinkle with mint and ready!