Dry-Spiced Aloo Gobi with Cumin and Tomato

Bake. Line a rimmed baking tray with paper towels. Mix potatoes, salt (2 tablespoons), vinegar, and 2 quarts cold water in a 3-quart saucepan. Bring to the boil over a high flame, next reduce heat to maintain a simmer. Cook till potatoes are tender plus offer little resistance when pierced using a paring knife, around 11 minutes. Tip off the liquid potatoes, move to ready baking tray, and leave till it is cold for no less than 20 minutes. Line a separate rimmed baking tray with paper towels. In a big Dutch oven or wok, heat oil over a high flame to 190°C. Tip in half of the cauliflower florets and cook, mixing lightly with a spider or tongs, till florets are gently browned and fully tender, around 2 minutes. Move florets to ready baking tray and season gently with salt. Return oil to return to 190°C and repeat with leftover florets. Return oil to 190°C. Add potatoes and cook, mixing now and then, till gently browned and crisp on the outside, around 2 minutes. Move potatoes to baking tray with cauliflower and keep to one side. Carefully move oil to a big heatproof bowl. Return oil to now-empty Dutch oven (3 tablespoons) or wok and heat over a medium-high flame till shimmering. Add cumin seeds and cook till seeds start to spit, around 10 seconds. Add onion and cook, mixing often, till onions just start to brown, around 8 minutes. Add ginger, garlic, and chiles and cook till fragrant, around 20 seconds. Mound vegetables in center of pan, tip in turmeric plus dried fenugreek leaves on top, plus mix well. Mix in chopped tomatoes and leftover 1 teaspoon salt and cook till tomatoes break down a little and release their liquid, around 2 minutes. Mix in water (1 cup), increase heat to high heat, and cook till liquid reduces a little, 2 to 3 minutes. Add set-aside cauliflower and potatoes and fold lightly to uniformly coat vegetables with sauce. Off-heat, mix in cilantro. Eat at once.