The burger recipes I've found online called for rather fatty ground beef, like 80% or 73%. (Spruce eats: 15 - 20% fat), Smoked BBQ source: 15 - 20% fat, Taste of Home: 20 - 40% fat (sic!), Spoon university: 20 - 30% fat, The Kitchn: 20% fat, Serious Eats: at least 20% fat, Steve Raichlen: 20% fat.) I didn't pay attention and bought some 90% lean beef. I guess the burgers will still work out, but it got me thinking.
If everybody says you need fatty ground beef for flavor, in what kind of recipes do you actually want these 90+% ground beefs, and why?