1/4 cup olive oil
1 cup frozen white pearl onions, thawed
4 garlic cloves, finely chopped
1 tablespoon chopped fresh sage
1 small bunch kale, center ribs and stems removed, leaves chopped
Kosher salt, freshly ground pepper
1/4 cup all-purpose flour
3 cups low-sodium chicken broth
1/2 small butternut squash, peeled, cut into 1/2-inch pieces (about 1 1/2 cups)
1/2 rotisserie chicken, meat torn into bite-size pieces (about 1 1/2 cups)
1 sheet frozen puff pastry (such as Dufour or Pepperidge Farm), thawed
1 large egg