1. In a large, wide pot, heat the butter over medium-high heat until bubbling. Add the celery, onion, garlic and red bell pepper and saute until vegetables are softened and the onion is translucent. Stir in the tomato paste.

2. Add the salt, dried thyme, celery seed, fennel, rosemary and chili powder (or chili flakes), chicken broth, beer and 1/2 lemon. Bring to a simmer and turn the heat to low. Let simmer for 10 minutes. Taste and season with more salt or chili powder if neeeded.

3. Turn the heat to medium-high and add the mussels to the broth. Immediately cover and let cook for 3 minutes. Open the lid and use a large spoon to redistribute the mussels—top to bottom; bottom to top. Cover and cook for an additional 2-3 minutes until all mussels are cooked through. Mussels are cooked through when they have opened. Discard any that do not open. Serve with French bread.