I just finished going through the whole process:
- Make sure your feat is there. I know you said you had the DLC, but it’s good to double-check if everything is installed and working properly
- Don’t place the horse yet! Keep it in your inventory.
- Craft tainted fodder in your firebowl cauldron. You’ll need 1 gruel, 1 yellow lotus and 1 aloe.
- Once you have your horse and your tainted fodder in your inventory, look up “White Horse” in your handcrafted recipes and craft it. My examples show black instead of white, but that’s just my preference – it’ll work for white horses too.
- Place your horse.
