Place the fresh arugula in a large salad bowl.
Add the roasted beet cubes to the arugula.
In a small bowl, whisk together the olive oil, balsamic vinegar, and Dijon mustard (if using). Add the minced shallot and honey or maple syrup if desired.
Drizzle the dressing over the arugula and beets.
Season with salt and freshly ground black pepper to taste.
Gently toss all ingredients until the leaves are lightly coated with dressing.
Sprinkle the toasted walnuts over the salad.
Finish by adding the crumbled goat cheese on top.
If using optional herbs or lemon zest, sprinkle them over the completed salad.
Serve immediately or chill for up to 15 minutes before serving.