01 - Toast the walnuts or pecans in a dry skillet over medium heat for 2 to 3 minutes, stirring frequently until fragrant, then remove from heat and let cool.
02 - Melt the butter in the same skillet over medium heat, then add pear slices and cook for 2 to 3 minutes per side until golden and lightly caramelized. Remove from heat and let cool slightly.
03 - In a small bowl, whisk together olive oil, balsamic vinegar, Dijon mustard, honey, salt, and pepper until fully combined.
04 - In a large salad bowl, combine mixed greens and red onion. Drizzle with half of the dressing and toss gently to coat.
05 - Arrange caramelized pears and toasted nuts over the greens, then sprinkle with goat cheese or feta if using.
06 - Drizzle remaining dressing over the salad just before serving.