Get your spinach out of the freezer to defrost.

Peel and slice onions in half lengthwise. Then slice each half into thin half moons. Place onions and lamb shanks (or other meat) in your slow cooker insert. Drizzle with a little oil and scatter over 1/2 teaspoon salt.

Turn oven to 200C (400F) and put the slow cooker insert in the cold oven. Cook for 30 minutes or until shanks are starting to brown.

Carefully transfer the hot insert to the slow cooker. Add tomato passata and rosemary (if using). Cover and cook on high for 6 hours or low for 11 hours or until meat is beautifully tender.

When you're ready to serve, squeeze spinach dry by placing in a sieve and pushing down with the back of a spoon. Discard the spinach juice. Stir spinach into the meat and leave on high to warm through for a few minutes. Taste and season with salt if needed.

Roughly chop almonds. Stir in most of the chopped almonds. Divide between 4 bowls and top with the remaining almonds.