Sugar pumpkins, small, smooth pumpkins that are great for cooking and baking, make for a satisfying and warming soup you’ll want to enjoy all season long. If you can’t find sugar pumpkin, kabocha squash, a sweet Japanese variety of winter squash, can be used in its place. Spicy harissa paste gives the soup a kick, but a dollop of Greek yogurt helps mellow the heat. To freeze, fill gallon-size freezer bags halfway with soup and freeze flat. To thaw, place in a bowl full of warm water for 10 minutes then reheat on the stovetop over medium heat.