Heat 2 tablespoons olive oil in a large saucepan over medium heat until shimmering. Add leeks, onions, garlic, and ginger, and cook, stirring frequently, until vegetables are softened but not browned, about 5 minutes. Add cumin, coriander, and harissa paste and cook, stirring constantly, until fragrant, about 1 minute. Add carrots and stir to coat in spice mixture. Add broth , season with a pinch of salt, bring to a boil, reduce to a bare simmer and cook, stirring occasionally, until carrots are completely tender, about 20 minutes.
