This would be quite tasty on arugula…If you can, make it an hour before serving, to allow the flavors to blend.
1/4 t salt
2 t extra-virgin olive oil
1 t dijon mustard
1 t fresh thyme leaves, chopped, if desired
1/2 c buttermilk, shaken to blend
1 garlic clove, minced or crushed, optional
1. Put all ingredients in a jar. Shake for about a minute. Let sit for an hour.