In a medium bowl, combine the lemon juice, Dijon mustard, minced garlic, salt, and black pepper. Whisk until well combined.
While continuously whisking, slowly drizzle in the olive oil in a thin, steady stream to create an emulsion.
Continue whisking for about 30 seconds after all oil has been added until the dressing is slightly thickened and uniform.
If using any optional ingredients like honey or herbs, fold them in and whisk to combine.
Taste and adjust seasonings as needed, adding more salt, pepper, or lemon juice to your preference.
Use immediately or transfer to an airtight container and refrigerate for up to one week.