2 Tbs. unsalted butter
1/2 cup thinly sliced leeks
1/2 cup finely chopped shallots
1/4 cup thinly sliced celery (halve lengthwise then slice crosswise)
2 tsp. minced garlic
Kosher salt
1 tsp. garam masala
5 cups homemade vegetable broth or low-salt chicken broth
3 Tbs. apple cider
2 lb. butternut squash, peeled, seeded, and cut into 1/2-inch dice
1/4 cup thick whole-milk yogurt, preferably Greek (I used the fat free plain yogurt I had in my house and it was fine)
Freshly ground black pepper
1-1/2 tsp. fresh lime juice
1/3 cup chopped fresh cilantro