Cook the bacon. Heat a large stockpot over medium-high heat. Add the bacon and sauté, stirring occasionally, until cooked and crispy. Use a slotted spoon to transfer the bacon to a clean bowl, leaving the grease behind.

Sauté the fennel and onion. Immediately add the fennel, onion and fennel seeds to the pot with the bacon grease. Sauté for 5-7 minutes, stirring every minute or two so that the edges can get a bit browned and caramelized. Add the garlic and sauté for 2-3 minutes, stirring more frequently.

Simmer. Add the broth, potatoes, rosemary, crushed red pepper flakes, and a few twists of black pepper. Continue cooking until the soup reaches a simmer. Then reduce heat to maintain the simmer, cover and cook for 10 minutes or until the potatoes are tender.

Season. Taste and season with additional salt and black pepper if needed.

Serve. Serve warm, garnished with the cooked bacon, chopped fennel fronds, and lots of chopped fresh chives. Enjoy!