Prepare the Turnips: Peel the turnips and chop them into rough 1-inch pieces.
Place them in a medium pot, cover generously with water, and bring to a boil.
Reduce the heat to a simmer, cover the pot, and cook for 15-20 minutes, or until the turnips are fork-tender.
Drain the water completely and mash the turnips well with a potato masher or fork.
Set aside.
Sauté the Aromatics: Heat the oil in a large nonstick frying pan or kadai over medium-high heat.
Once the oil is shimmering, add the cumin seeds and let them sizzle for about 10-15 seconds until fragrant.
Add the chopped onion and sauté for 5-6 minutes, stirring occasionally, until softened and lightly golden.
Build the Masala Base: Stir in the grated ginger, chopped garlic, and green chilies.
Sauté for another minute until the raw smell disappears.
Add the chopped tomatoes and cook for 5-6 minutes, stirring and mashing them with your spoon, until they break down into a thick, paste-like consistency and you see oil separating at the edges of the pan.
Combine and Sauté: Add the mashed turnips and salt to the pan.
Mix everything thoroughly.
Reduce the heat to medium-low and cook for 20-25 minutes, stirring frequently to prevent sticking. This slow sautéing step is crucial for developing a deep, roasted flavor. The bharta is ready when it has darkened slightly and looks well-integrated.
Finish and Serve: Stir in the freshly ground black pepper and 3 tablespoons (45 ml / 1.5 fl oz) of the chopped cilantro.
Mix well to combine.
Transfer the bharta to a serving dish and garnish with the remaining 1 tablespoon (15 ml / 0.5 fl oz) of cilantro.
Serve hot.