This slow cooker 3-ingredient onion and potato soup is the kind of humble, filling meal my grandpa swore by during the lean years. Back in the Depression, folks around here had to stretch every penny, and a sack of potatoes, a few onions, and a bit of fat or broth could keep a family going.
This version leans on time and gentle heat to coax deep, rich flavor out of almost nothing. The onions slowly caramelize in their own juices, the potatoes turn tender and creamy, and the broth takes on a golden color and a silky, slightly thickened texture. It’s simple, honest food that fills you up and warms you clear through without asking much from your pantry or your wallet.

Ladle this soup into sturdy bowls and serve it with thick slices of crusty bread or simple buttered toast for dipping into the rich broth. A crisp side salad of whatever greens you have on hand adds a bit of freshness, but it’s not required; this soup stands on its own as a full meal, especially on cold evenings.
If you like, offer a little black pepper at the table for those who want more bite, but otherwise let the pure flavors of onion, potato, and broth shine the way our grandparents enjoyed them.
Slow Cooker 3-Ingredient Onion and Potato Soup