Clean the mussels by scrubbing them under cold water and removing any beards or barnacles.

Heat the olive oil in a large pot over medium heat. Add the chopped onion and minced garlic and cook until softened.

Pour in the white wine and bring it to a simmer.

Add the mussels to the pot and cover it with a lid. Steam for about 5-7 minutes until the mussels have opened.

Remove the mussels from the pot and set aside. Discard any mussels that did not open.

Add the spinach to the pot and cook until wilted.

Season with salt and pepper to taste.

Serve the mussels and spinach in bowls, spooning some of the cooking liquid over the top.

Enjoy!