I started making this keto minestrone because I missed the big, brothy Italian soups I grew up eating. Regular minestrone is loaded with pasta and kidney beans, so I had to rethink the whole thing. The parmesan cheese rind is what makes this version work. It melts slowly into the broth over 20-plus minutes and gives the soup a savory depth that you’d swear came from simmering all day. I keep a bag of rinds in my freezer specifically for soups like this and my keto beef tomato soup.
The other piece that makes this different from most low carb vegetable soups is the lupini beans. I’ve gotten more questions about these beans than almost any other ingredient on the site. They’re naturally firmer than cannellini or great northern beans, and that’s intentional. They hold their shape through simmering, through reheating, through everything. Cannellini fall apart after a day in the fridge. Lupini don’t. One reader (Rita) told me she’d been making traditional minestrone with cannellini for years and actually prefers this version now. That was a big compliment.
I use cauliflower rice instead of pasta or regular rice, which keeps the carb count down without leaving the soup thin. You barely notice the swap once everything has simmered together. The bacon adds smokiness, but if you want a vegetarian version, swap it for 2 tablespoons of olive oil and use vegetable broth. I’ve done it both ways and the parmesan rind carries enough flavor on its own. One more note for strict vegetarians: parmesan is made with animal rennet, so use a rind from a vegetarian hard cheese if that matters to you.
One thing I’ve learned from making this dozens of times: don’t add the spinach until the very end. It wilts in about 30 seconds and overcooking it turns the whole pot a muddy green. Same goes for freezing. If you’re meal prepping, leave the spinach out of the batch you’re freezing and stir in fresh leaves when you reheat. The soup itself freezes well for up to 3 months.
If you’re into keto soups, this pairs well with a rotation. I cycle through this, my keto chicken and rice soup, keto turkey soup, and keto cheeseburger soup depending on the week. This one is my go-to when I want something lighter but still filling.
