In a large bowl, mix the flour and salt.
Gradually add the warm water and vegetable oil, mixing until a dough forms.
Knead the dough on a floured surface for about 5-7 minutes, or until smooth and elastic.
Cover the dough with a damp cloth and let it rest for 30 minutes.
In a mixing bowl, combine the ground beef or lamb, chopped onion, minced garlic, soy sauce, salt, black pepper, and ground cumin if using.
Mix well until all ingredients are thoroughly combined.
Divide the dough into small balls (about the size of a golf ball).
On a floured surface, roll each ball into a thin circle.
Place a spoonful of the filling in the center of each circle.
Fold the dough over the filling to create a half-moon shape. Pinch the edges together to seal, or crimp with a fork to ensure the filling is enclosed.
Heat a generous amount of vegetable oil in a skillet over medium-high heat.
Fry the khuushuur in batches, cooking each side until golden brown and crispy, about 2-3 minutes per side.
Remove from the skillet and drain on paper towels.
Enjoy your meal!