In a jar or small bowl, whisk together all of the ingredients until fully blended. Sometimes, if your mustard is cold, it will need a few minutes to warm up before it fully incorporates.

Taste, and adjust if necessary—for more tartness, add another teaspoon of apple cider vinegar, or for more sweetness/balance, add another teaspoon or two of maple syrup (I usually add one).

This salad dressing will keep well in the refrigerator for up to 10 days. Real olive oil can solidify slightly when cold; if that happens, simply let it warm to room temperature for a few minutes or microwave it in a microwave-safe jar for no more than 15 to 30 seconds.