Nutrition per serving may change if servings are adjusted.
2½ pounds delicata or acorn squash (see Tip)
3 tablespoons extra-virgin olive oil, divided
2 tablespoons whole-grain mustard, divided
3 cloves garlic, minced
1 tablespoon chopped fresh rosemary or 1 teaspoon dried
1 teaspoon grated lemon zest
2 tablespoons lemon juice, divided
1 teaspoon ground pepper, divided
½ teaspoon salt, divided
1 pound boneless, skinless chicken breast
1 tablespoon pure maple syrup
1½ teaspoons fresh thyme leaves
8 cups mixed salad greens
4 teaspoons grated Parmesan cheese
4 teaspoons salted roasted pumpkin seeds
Preheat oven to 425°F. Coat a large rimmed baking sheet with cooking spray.
Cut squash in half lengthwise and remove seeds. Cut crosswise into 1-inch slices.
Combine 1 tablespoon oil, 1½ tablespoons mustard, garlic, rosemary, lemon zest, ½ tablespoon lemon juice, ½ teaspoon pepper, and ¼ teaspoon salt in a large bowl. Add chicken and the squash and stir to coat. Arrange in a single layer on the prepared pan.
Bake, without stirring or flipping, until the squash starts to brown and the chicken reaches an internal temperature of 165°F, 20 to 22 minutes. Transfer the chicken to a clean cutting board and slice.
Meanwhile, whisk the remaining 2 tablespoons oil, ½ tablespoon mustard, 1½ tablespoons lemon juice, maple syrup, thyme, and the remaining ½ teaspoon pepper and ¼ teaspoon salt in a medium bowl. Add greens and toss to coat.
Divide the greens among 4 serving plates. Top with the chicken and squash, Parmesan, and pumpkin seeds.
Tip: You can find delicata and acorn squash in the produce section of many grocery stores. Delicata squash has an edible rind, but acorn squash does not, so you can remove the rind of acorn squash before serving or simply eat around it.