Preheat your oven to 400°F (200°C).
Cut pears in half or thick slices. Remove cores.
Toss pears with olive oil, salt, and pepper.
Place pears cut-side down on a lined baking sheet.
Roast for 20–25 minutes, flipping once halfway. Set aside to cool slightly.
Lower oven temperature to 350°F (175°C).
Toss walnuts with olive oil and salt.
Roast walnuts for 6–8 minutes until lightly toasted. Let cool.
In a large bowl, add arugula and mixed greens.
Arrange roasted pears on top.
Sprinkle roasted walnuts and feta cheese over the salad.
Whisk all dressing ingredients in a small bowl.
Drizzle dressing lightly over the salad.
Toss gently and serve right away.