Begin by preheating your oven to 350°F to ensure it's at the correct temperature for roasting.

In a small bowl, whisk together the sugar, ginger, and cardamom until the spices are thoroughly distributed throughout the sugar.

Arrange the rhubarb pieces in an ovenproof dish and sprinkle the sugar-spice mixture over them, tossing gently to ensure every piece is evenly coated. Cover the dish tightly with foil to lock in moisture.

Bake in the preheated oven for 15 to 30 minutes. You'll know it's ready when the rhubarb is tender enough to be pierced with a fork but still retains its distinct shape; check it every 10 minutes to prevent it from turning into mush.

Once tender, remove the dish from the oven and let it cool. Carefully lift the rhubarb out using a slotted spatula to keep the pieces intact.

If the remaining syrup seems too thin, pour it into a small saucepan and simmer over medium heat until it thickens into a glossy glaze.

To serve, spoon the rhubarb into bowls, add a generous dollop of cold yogurt, and drizzle the concentrated syrup over the top.