Recipe # 1 had - Sour cream
Recipe # 2 had - Sour cream
Recipe # 3 had - Evaporated milk
Recipe # 4 had - Sour cream
Recipe # 5 had - Yogurt
Recipe # 6 had - Sour Cream
See the pattern? Most of them also had less than a tablespoon (15 ml) of horseradish in a pint (2 cups, 473 ml) of finished sauce. I usually use 1 tablespoon (15 ml) per 1/4 cup (59 ml) sauce or about 1/2 cup per pint. (My basic horseradish sauce is in this post)
We have decided to go "soy free" so making or buying my usual fake sour cream, evaporated milk, or yogurt just to test the recipes is out. The best scratch recipes for soy-free vegan sour cream use another ingredient I react badly to. I need a degree in comparative vinegar!
We also don't like the new coconut milk products. That 's the next suggested substitute - coconut milk cultured yogurt, drained and mixed with lemon juice. I've done that with silken tofu and back in the before allergies ruled my diet I did this with dairy yogurt.. It works for cooking with and for making some dips.
What it comes down to is that I've got to experiment and make my own my mustard - horseradish sauce because the rest of the world doesn't have the same allergies or tastes that I do. IF it turns out yummy, I'll post it.
Edit:I made a sauce that was very yummy. Measurements are approximate.
1/4 cup +/- Mayonnaise
2 tablespoons +/- Stone Ground Mustard
1 tablespoon +/- prepared horseradish
Mix well. Serve with beef or pork. It is a bit overpowering for poultry