Wash and dry the spinach leaves.
Place them in a large salad bowl.
Add the sliced strawberries, toasted pecans, and red onion to the bowl.
In a small bowl or a jar with a lid, combine the balsamic vinegar, olive oil, honey, Dijon mustard, salt, and pepper.
Whisk or shake well until all theingredients are thoroughly mixed.
Drizzle the dressing over the salad just before serving.