Preheat oven to 425ºF. Prepare large baking pan by lining with parchment paper.
Put diced squash onto pan, add olive oil, sage, salt, and pepper. Stir well, coating squash with oil. Bake 20 minutes or until soft and lightly browned. Do not overcook. Squash should be bite tender, not mushy.
To prepare crostini, spread approximately ½ tablespoon of ricotta on each prepared bread slice.
Arrange roasted squash cubes, pomegranate arils, and peitas on crostini.
Drizzle with pomegranate molasses.
Use honey or balsamic reduction instead of pomegranate molasses, if desired.
Other types of spreadable cheese can be used instead of ricotta.
Make Ahead: Crostini can be made a couple of days ahead, cooled thoroughly, and stored in an airtight container. Squash can be prepped and cut up to 3 days in advance; refrigerate. Squash can be roasted up to one day in advance; cool completely and store in refrigerator.