In a medium bowl, combine the extra-virgin olive oil and balsamic vinegar. Whisk vigorously until the mixture begins to emulsify slightly.
Add the finely chopped fresh basil and minced garlic to the oil-vinegar mixture. Whisk to incorporate.
Season with sea salt and freshly ground black pepper, whisking to combine thoroughly.
If using any optional ingredients (honey, Dijon mustard, sun-dried tomatoes, or Parmesan), add them now and whisk until fully incorporated.
Taste the dressing and adjust seasonings if needed. For more acidity, add a touch more vinegar; for richness, a bit more olive oil.
Let the dressing sit for at least 10 minutes before serving to allow flavors to meld.
Before serving, whisk again or shake well if stored in a jar. Use immediately or refrigerate.