Heat oil on sear setting in crockpot and add onion plus 1 tsp of salt. Cook until onion starts to soften, stir in garlic. Cook 2 minutes more until garlic smells fragrant.

Add beef, breaking it up into chunks with a spoon, and season with another 1/2 tsp of salt. Cook until well browned (this step can take a while, you can skip it if short on time, but it does add a lot of flavour).

Stir in tomato paste to evenly coat everything and cook until it the paste turns a shade darker and smells toasty, about 5 minutes. Stir in eggplant (if using), pureed tomatoes and remaining salt.

Close crockpot lid and cook on high setting for 4 hours or on low setting for 6 hours (longer cooking is perfectly fine if you've got more time!).

Taste sauce and add more salt by small pinches as needed until it tastes bright and flavourful.