Heat half of the ghee in a large skillet or casserole dish over medium-high heat.
Add the diced halloumi and cook until lightly browned on all sides. Use a slotted spoon to transfer the halloumi to a bowl and set aside.
Add the remaining ghee to the pan.
Add the cumin seeds and cook for 30 seconds over medium-high heat until they become fragrant.
Add the sliced onion and cook for 2 to 3 minutes.
Stir in the garlic, ginger, and green chile pepper, followed by the ground coriander, garam masala, turmeric, and chili powder.
Cook for 1 minute, stirring frequently to prevent burning.
Pour in the tomatoes and vegetable stock, stirring to combine.
Cook for 1 to 2 minutes, allowing the sauce to start thickening.
Add the sliced bell peppers and diced zucchini to the skillet.
Cook for 5 to 8 minutes, or until the vegetables are crisp-tender.
Return the browned halloumi to the pan and stir to coat.
Season with salt and pepper to taste.
Remove from the heat, drizzle with fresh lemon juice, and garnish with cilantro before serving. Store leftovers in an airtight container in the refrigerator for up to 5 days.
