Rinse the wheat grains, barley, split chickpeas, red lentils, and rice under cold water.
Soak them in water for at least 2 hours or overnight for best results.
In a large pot, heat the oil or ghee over medium heat.
Add the chopped onions and sauté until they become golden brown.
Stir in the garlic and ginger paste, and cook for an additional minute.
Add the meat pieces and cook until they are browned on all sides.
Add the chopped tomatoes and cook until they soften.
Stir in the yogurt, cumin, coriander, turmeric, red chili powder, garam masala, and chili flakes (if using). Cook for 5 minutes.
Add the soaked grains and lentils to the pot, and mix well.
Pour in the water or broth, and bring the mixture to a boil.
Reduce the heat to low, cover the pot, and let it simmer for 2-3 hours, stirring occasionally. The mixture should become thick and porridge-like. You can use a hand blender to blend some of the ingredients for a smoother texture if desired.
Once the Haleem has reached the desired consistency and flavor, adjust the salt to taste.
Garnish with chopped coriander leaves, fried onions, fresh mint leaves, and sliced green chilies.
Enjoy your meal!