Next, we get the fennel ready. We cut off the fronds, reserving a bit of the greenery for garnish after rinsing well. We trim a small slice off the bottom of the fennel bulb and rinse and dry. We cut off any blemished areas (it looks good) and then we halve it crosswise and slice lengthwise into small pieces. We add this to the garlic and oil and continue to cook slowly, sweating the vegetables.
The pasta water is almost to a boil and we lower the heat on the pot. We clean the mussels in the kitchen sink with cold water. We rinse each mussel scrubbing any debris. We want the mussels tightly closed, any that are a but open we tap on the sink and set aside on the counter to be sure that they close on their own. Any mussel that is not tightly closed we discard. After we rinse and scrub a mussel, we pull out the “beard”, a “hairy” piece that sticks out of some of the mussels. We place them into the rinsed out bowl that was under the colander.
When the mussels are all cleaned, we raise the heat on both the pasta water pot and the garlic and fennel pot. We add the wine to the fennel pot and when the wine comes to a boil, we add the mussels, and cover the pot.
The mussels only take a few minutes to open so we add the pasta to the pot of boiling water along with some salt. When the mussels have been cooking for two minutes, we stir them and any mussels that have opened we remove to a serving bowl with tongs. We cover again and check after a minute. When all the mussels are done (they all opened), we add the parsley to the fennel sauce along with a squeeze of the lemon half. When the pasta is done, we drain it into a clean colander and toss with the fennel sauce.
We serve the pasta, topped with some mussels, fennel fronds, and red pepper flakes.