Adjust the oven rack to the middle position and heat to 450°F. Toss the cauliflower with the olive oil, cardamom, cumin, salt, and pepper on a rimmed baking sheet until evenly coated.

Roast the cauliflower until it is tender and the edges are browned, about 20 to 25 minutes, tossing the florets halfway through to ensure even coloring.

Heat the remaining olive oil in a large saucepan over medium-high heat until it shimmers. Add the onion and a pinch of salt; cook until the onion is softened and turns a deep golden brown, 6 to 8 minutes.

Stir in the garlic, jalapeño, cinnamon, and ginger. Cook until the mixture is fragrant and the garlic has softened.

Add the rinsed rice and cook, stirring frequently, until the edges of the grains look translucent, about 2 minutes. Pour in the water and salt, then bring the mixture to a boil.

Reduce the heat to low, cover the pan tightly, and simmer until the rice is tender and the liquid is fully absorbed, about 15 minutes.

Remove the pan from the heat. Scatter the currants and crumbled saffron over the top of the rice, but do not stir. Cover and let the pot stand for 10 minutes to allow the saffron to bloom and the currants to plump.

Gently fold in the roasted cauliflower, cilantro, and mint using a fork to keep the rice grains separate and fluffy. Serve immediately while hot with the yogurt-herb sauce.