I’m not @BigWoodenSpoon, but here’s an old one from Tyler Florence which is terrific:
1/2 c. mayo
1/2 c. + 1-2 T. good blue cheese (Maytag, for instance)
1/4 + 1-2 T. whole buttermilk
1/8 t. fresh squeezed lemon juice
1/4 t. Worcestershire sauce
1/4 t. kosher salt
1/8 t. celery seed
10 cranks (+/-) freshly ground black pepper
Pulse everything in a food processor to desired texture. If you like, whisk in a few more chunks of blue cheese after processing for a chunkier texture.