Preparation Heat butter and olive oil in a 3-4 quart dutch oven or heavy-bottomed saucepan with a tight-fitting lid. When oil shimmers, add onion, garlic, cumin, and cinnamon stick, and season with salt and pepper. Cook, stirring occasionally, until spices are aromatic and onions are soft and translucent, about five minutes. Add squash and tomatoes, stir to coat, and cook 3-5 minutes, until squash is still very firm but beginning to soften. Add broth, chickpeas, tomatoes with their juices, and saffron. Bring to a boil, lower heat, and simmer with lid on about 10 minutes, or until squash is tender. Remove from heat and stir in olives and preserved lemon. Serve over couscous with cilantro, almonds and yogurt.