Rinse the Mussels:

• Place the mussels in a large bowl of cold water.

• Scrub the shells and remove the beards.

• Discard any mussels that are cracked or remain open after tapping.

Heat the Oil and Butter:

• In a large pot or Dutch oven, heat the olive oil and butter over medium heat.

Sauté the Vegetables:

• Add the onion, garlic, and leeks, and sauté for 5-6 minutes until soft and fragrant.

Add the Saffron:

• Add the saffron threads to the pot and stir for 1 minute to release the aroma.

Deglaze with Wine:

• Pour in the white wine and simmer for 2-3 minutes, allowing the alcohol to evaporate.

Add the Broth and Tomatoes:

• Add the vegetable broth, diced tomatoes, thyme, and red pepper flakes.

• Season with salt and black pepper.

• Bring to a gentle boil and simmer for 5 minutes.

Add the Mussels:

• Increase the heat to medium-high.

• Add the mussels to the pot and cover with a lid.

• Steam for 5-7 minutes, or until the mussels open.

Discard Unopened Mussels:

• Remove and discard any mussels that do not open during cooking.

Add the Cream and Lemon Juice:

• Reduce the heat to low and stir in the heavy cream and lemon juice.

• Simmer for 2 minutes to meld the flavors.

Adjust Seasoning:

• Taste and adjust with additional salt, pepper, or lemon juice as needed.

Ladle the Soup:

• Divide the soup among serving bowls, ensuring each bowl has a good portion of mussels.

Garnish:

• Sprinkle with fresh parsley and serve with lemon wedges and crusty bread for dipping.