Whether you’re using 1 tablespoon fresh or 1 teaspoon dried oregano, crush it between your fingers to release it’s oils, then add it to a small jar. Add 1/4 cup red wine vinegar, the juice of 1 lemon, 1 teaspoon Dijon mustard, 1/4 teaspoon garlic powder, 1/4 teaspoon salt, and 1/4 cup olive oil. Shake vigorously to combine, for 15 to 20 seconds. Taste the dressing. Do you want it to be thicker? Add more olive oil. Adjust salt to taste if needed.