This creamy, comforting squash soup stars harissa, a bright, tangy-hot chili paste from northern Africa. Harissa varies in heat level, so use more or less depending on the brand and your spice tolerance. Paprika adds smoky sweetness, while cumin contributes warm, earthy notes. We bloom the seasonings in oil to enhance their flavors and aromas. Leeks’ many layers can trap sand and dirt, so wash them thoroughly and drain them well before use. Toasted pumpkin seeds bring body, flavor and richness and provide texture as a crunchy garnish. Serve dolloped with plain yogurt for a touch of cool creaminess.