Does the "make your own buttermilk!" trick not work? The one where you add a little bit of vinegar or lemon juice, or some other acid, to whole milk and let it thicken (I think it takes 5 minutes?). Loads of websites offer that trick.
Edited to add...
My Cajun spice mix is:
3 parts paprika
2 parts garlic powder
1.5 parts salt
1 part onion powder
1 part cayenne
1 part ground black pepper
1 part oregano
1 part thyme
Makes 11.5 (whatever you're measuring your parts with). I use a half-teaspoon, so a single batch for me is 5.75 teaspoons (a little under two tablespoons, or about one ounce). But I use it on ALL the things, so I usually make at least a double batch... sometime triple. And last time, I did a quadruple batch, so haven't had to make it for a couple of weeks. It's been nice.
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