Connie - though grated mozzarella would also melt nicely, it won't contribute the salty/tangy quality that we love about feta in this recipe. A great substitute, if your husband likes it, would be a soft goat cheese, which has a similar creamy/crumbly texture and a brightness to balance out the rich flavors here. If that's a no-go, then go with mozzarella, but add a tablespoon or two of lemon juice, plus a sprinkle of lemon zest, to stand in for the feta's tartness.

Best,
The Milk Street Team

Pamela - this is a recipe where subbing in ground lamb instead of ground beef is an easy substitution. Go for it! Keep in mind that the fat content of ground lamb is quite variable. Compared to beef, lamb has less marbling within the meat: most of its fat is around the exterior, and is usually trimmed away before being ground, resulting in a slightly leaner ground meat than beef. If you are getting ground lamb from a butcher, just let them know that you are looking for about an 80/20 meat/fat ratio - comparable to ground beef - and they should be able to make it just right for you. Even if your lamb is a touch fattier or a little leaner than a lean ground beef, the recipe will still come out just fine.

Best,
The Milk Street Team

I made this with ground bison, and it came out great.

By the way, your comment about looking for an 80/20 meat/fat ratio contradicts the instructions at the top of the recipe ("Tip: Don't use ground beef fattier than 90 percent lean or the sauce will be greasy.").

Hi William -

You're right. We almost always call for 80/20 ground beef, so I think April just missed the note that we actually call for 90/10 in this recipe. As she mentioned, ground lamb can be quite variable, though, so you may have to drain off some fat if the lamb you use happens to be fattier.

Best,
The Milk Street Team