01 - Melt butter in a nonstick skillet over medium heat. Add walnuts and sugar, stirring constantly until sugar melts and evenly coats nuts, approximately 3 to 4 minutes. Transfer to parchment paper, spreading to separate clusters while cooling completely.
02 - Whisk together olive oil, balsamic vinegar, Dijon mustard, honey, salt, and pepper in small bowl or jar until emulsified. Reserve at room temperature until serving.
03 - Place spinach, sliced strawberries, red onion, and goat cheese in large salad bowl. Toss lightly to distribute ingredients evenly.
04 - Fold cooled candied walnuts into salad mixture, ensuring even distribution throughout bowl.
05 - Drizzle balsamic vinaigrette over salad immediately before serving. Gently toss to coat all ingredients without crushing spinach. Serve promptly to maintain crisp texture.