To make the curry: Heat the oven to 400 F. Place the cauliflower on a sheet pan, drizzle with 2 teaspoons of the oil and toss to coat. Sprinkle with 1 teaspoon of the garam masala, season with salt and pepper and toss to coat. 

Place the chickpeas on a second sheet pan, drizzle with 1 teaspoon of the oil and toss to coat. Sprinkle with ½ teaspoon of the garam masala, season with salt and pepper and toss to coat. 

Roast the cauliflower and chickpeas for 25 to 30 minutes, stirring halfway through, until the cauliflower is fork tender and golden brown and the chickpeas are crispy. 

In a large non-stick skillet, heat 2 teaspoons of the oil over medium-high heat. Add the onions and sauté until translucent, 4 to 5 minutes. 

Add the turmeric and chili powder and cook for 30 seconds. Reduce the heat to low and add the chickpea flour. Cook, stirring constantly, for 2 to 3 minutes, until toasted. 

Stir in the kefir and bring to a simmer over medium heat. Cook, stirring constantly, until the sauce thickens slightly, 2 to 3 minutes. Season with salt and pepper. 

Fold in the roasted cauliflower and ⅔ of the crispy chickpeas. Keep warm over low heat.

To make the chile oil: Heat a small saucepan over medium-high heat. Add the cumin and mustard seeds, and cook until fragrant, 30 seconds. Add the oil and cook until hot, 1 minute.

Transfer the oil and seeds to a heatproof bowl and stir in the chile flakes.

To serve, garnish the curry with the remaining chickpeas and chile oil. Scatter the cilantro on top. Serve hot with brown rice.