Add juice of one lemon to a medium pot of water and bring to a boil. Add about 10 grape leaves and cook for 1 ½ minutes until they begin to change to an olive color. Drain then wash with cold water.
Core grey squash and set aside.
Soak rice in water for 10 minutes, drain and mix with, ground beef, chopped onion, parsley, chopped garlic, black pepper, cumin, turmeric and olive oil.
Lay out a grape leaves and place a small amount of rice in the middle, roll it up and repeat.
Fill grey squash with the same rice mixture.
Add a tablespoon of oil, garlic cloves, sliced onions, potatoes and tomatoes to the bottom of a large pot. Add a single layer of rolled grape leaves, then all of the stuffed squash. Fill the pot with the rest of the grape leaves then add salt, lemon juice and about 4 1/2 cups of water, until it reaches just under the top layer of grape leaves. Cover with an upside down plate to weigh it down. Cook for 1 hour and 45 minutes on medium heat or until the rice is cooked all the way through.
Remove the lid and plate and carefully flip onto a tray. Serve and enjoy!