In a food processor,
- add the scallions, basil, lemon juice, mustard, olive oil, garlic, salt and pepper to the work bowl and pulse a few times to incorporate.
- You don’t want to puree this, just blend it up a little.
- Add the mayonnaise and yogurt and pulse once or twice again to blend.
- Scrape into a jar and refrigerate.
If you don’t have green onions, you can substitute finely chopped shallots or sweet red onion to equal 1/4 cup.
Basil is my preferred herb here but you can replace it, all or in part, with parsley. A bit of fresh tarragon is nice, too, although I add about 1 tablespoon of finely chopped tarragon to the 1/2 cup of parsley instead of doing the full 1/2 cup substitute.
Variation: Sprinkle in a bit of powdered chipotle or smoked paprika for some smokey heat!