1. 1. Prepare the Spinach: Start by gently washing the baby spinach under cool water. Pat it thoroughly dry with paper towels or use a salad spinner to remove excess moisture. Place the dried spinach in a large mixing bowl.

2. 2. Slice the Strawberries: Hull the fresh strawberries by removing the green tops. Slice them into bite-sized pieces, typically quarters or halves depending on their size. Add the sliced strawberries to the bowl with the spinach.

3. 3. Add the Feta and Nuts: Crumble the feta cheese directly over the spinach and strawberries. Sprinkle the chopped pecans or walnuts evenly over the salad. If using, add the thinly sliced red onion at this stage as well.

4. 4. Whisk the Dressing Ingredients: In a small bowl or a jar with a tight-fitting lid, combine the olive oil, balsamic vinegar, honey (or maple syrup), and Dijon mustard.

5. 5. Season the Dressing: Whisk the dressing vigorously until all ingredients are well combined and emulsified. Taste and season with salt and freshly ground black pepper as needed. Adjust the sweetness or tanginess to your preference.

6. 6. Dress and Toss the Salad: Just before serving, pour the prepared dressing over the salad ingredients in the large bowl. Gently toss everything together until the spinach, strawberries, feta, and nuts are evenly coated with the dressing. Serve immediately.