We chose a combination of yellow, red, white ... Each component of this recipe — the roasted squash, caramelized onions, and croutons — can be made up to three days in advance.
Set aside. As squash roasts, heat a skillet over medium heat. Add butter and melt. Add onions and cook, stirring, until caramelized, about 25 minutes. Place individual flatbreads on a baking sheet ...