Lay the puff pastry over the skillet for a pretty look. Use any brand; the weight may vary, but either way you'll have enough to work with.
Prep: 30 mins
Cook: 1 hr 15 mins
Yields: 6 Servings
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" 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
1Place a rack in upper third of oven; preheat to 425°F. Heat oil in an 8" cast-iron or other heavy ovenproof skillet over medium-high heat. Add onions; cook, stirring occasionally, until beginning to brown, about 4 minutes.
2Reduce heat to medium-low. Add garlic and sage to skillet and cook, stirring occasionally, until garlic begins to brown, about 2 minutes.
3Add kale and season with salt and pepper. Cook, tossing often, until wilted, about 4 minutes. Sprinkle flour over. Cook, stirring constantly, for 4 minutes.
4Stir in broth, 1/2-cupful at a time, then add squash. Bring to a boil, reduce heat, and simmer until squash is just softened and broth is thickened, 8-10 minutes. Add chicken to skillet, stir, and season with salt and pepper.
5Unfold pastry and smooth any creases; place over skillet, allowing corners to hang over sides. Whisk egg and 1 teaspoon water in a small bowl. Brush pastry with egg wash; cut four 1" slits in top to vent.
6Bake pot pie until pastry is beginning to brown, 15-20 minutes. Reduce oven temperature to 375°F and bake until pastry is deep golden brown and crisp, 15-20 minutes longer. Let cool for 10 minutes before serving.