Step 1

Combine chiles, vinegar, sugar, ½ tsp. salt, and ¼ cup water in a small bowl. Let sit at room temperature until ready to use.

Step 2

Preheat oven to 450°. Toss cauliflower with olive oil, vadouvan, and 1 tsp. salt on a rimmed baking sheet. Roast, tossing occasionally, until cauliflower is tender and browned, 30–35 minutes. Transfer to a paper towels to drain.

Step 3

Meanwhile, cook shallots in ½ cup vegetable oil in a small saucepan over medium-high, stirring occasionally, until golden brown and crisp, 8–10 minutes. Transfer to paper towels with a slotted spoon; season with salt.

Step 4

Heat remaining ¼ cup vegetable oil in a large skillet over medium. Add onion and cook, stirring often, until tender, 5–7 minutes. Add ginger, garlic, and lemongrass and cook, stirring constantly, until fragrant, about 1 minute. Add tomato paste and harissa pasta and cook, stirring constantly, until slightly darkened in color, about 2 minutes.

Step 5

Whisk in coconut milk, bring to a boil, and cook, whisking occasionally, until curry thickens to the consistency of heavy cream, 5–7 minutes. Add chickpeas and ¼ cup water and cook, stirring occasionally, until mixture returns to a boil. Remove from heat and stir in cilantro stems; season with salt.

Step 6

Serve curry over rice topped with drained pickled chiles, roasted cauliflower, fried shallots, and cilantro sprigs.