Recipe(tried): Some suggestions: Fix for Too Much Black Pepper

I've had to salvage plenty of soups and stews myself . . . So I feel your pain.

In my own experience, in the case of too much pepper, I would say the best thing would be to try to tone it down with something dairy. Sour cream or cream cheese can be good. Even just milk might help. Sometimes I even add regular cheese where appropriate I guess it would depend on what else the stew has in it. Of course, this will change the consistency from thin to creamy, if that's a problem, I would just say add more water and maybe some more mild veggies like tomatoes, celery, potatoes, or carrots.

Actually, you might try straining the liquid part of the soup with a sieve or a slotted spoon covered in a paper towel. That way the water runs out but the pepper gets stuck.

Or . . . If the base of the stew is thin you could just eat the stew carefully. I've noticed that with thinner liquid, the pepper and spices tend to sink to the bottom of your bowl, so you could let it settle and not drink the last bit of soup that is all peppery and throw that part out, that way you're wasting a lot less than a whole stew. :)
Hopefully this was helpful. Happy Cooking!
~Julie :}