Some dishes are divas, and there’s no substitute. Creme brulee? Use half-and-half, and you’ll get pudding, not a silky custard. Panna cotta also needs that fat to set properly. Don’t argue with Italian desserts—they’ve been around longer than you.
What about chowders? A clam chowder with half-and-half will be thinner, but you can cheat with extra potatoes. Yukon golds are your allies here. Mash a few into the broth for body.