In a small bowl, whisk together balsamic vinegar, salt, and pepper.
Slowly pour in olive oil while whisking constantly.
Put spinach into a large serving bowl, then pour in a small amount of the dressing. Toss until coated.
Top with beets, goat cheese, and pecans.
Serve with remaining dressing on the side.
Notes
Storage Tips: Keep the vinaigrette out at room temperature in a small mason jar. The spiced pecans should also be kept at room temperature. Refrigerate the spinach, beets, and goat cheese separately. They will all last for up to 5 days. If you have leftovers of a fully assembled salad, remove the pecans before refrigerating, as the coating on them will melt into the salad. Refrigerate the rest of the salad—it should keep for about 24 hours before the spinach becomes too wilted to enjoy.Expert Tips: This salad is beautiful in a large salad bowl, but also can be plated individually for a dinner party. To plate individually, toss spinach with a small amount of dressing, then divide onto each plate. Then top each plate with beets, goat cheese, and pecans.