As Carolina said, you can omit the bell peppers and onion family products for other peppers or leeks, shallots, etc.. (theplantphilosophy.com)
I make a broccoli / leek soup (although sometimes lacking leeks I just use whatever onion family stuff I've got in the kitchen)- and accent it with creme fraiche blended with lemon juice and chives - it's nice to have the hot and cold contrast. (101cookbooks.com)
d. Onion family — onions, garlic, leeks and chives are more toxic to cats than dogs, but dogs will eat these herbs before cats. (boyetteanimalhospital.com)