01 - In a small mixing bowl, whisk together olive oil, balsamic vinegar, Dijon mustard, honey, sea salt, and black pepper. Continue whisking vigorously until the mixture is fully emulsified and creamy. Set aside at room temperature.
02 - Place the washed and dried baby spinach in a large salad bowl, creating a generous bed of greens. Evenly distribute the sliced strawberries, toasted walnuts, and thinly sliced red onion over the spinach. If using, scatter the crumbled feta cheese across the top.
03 - Drizzle the prepared balsamic vinaigrette evenly over the salad. Using salad servers or large spoons, gently toss the ingredients together, lifting from the bottom to ensure all leaves are lightly coated with dressing. Avoid over-mixing to prevent bruising the delicate spinach.
04 - Transfer to individual serving plates or present family-style in the large bowl. For an attractive presentation, garnish with additional toasted walnuts or fresh strawberry slices if desired. Serve promptly while the walnuts remain crunchy and the spinach is crisp.