Steamed Mussels in White Wine and Garlic Broth

Rinse the mussels under cold running water, scrubbing off any grit with your fingers or a brush.
Pull off the fibrous 'beard' sticking out of each shell by pinching it and tugging firmly toward the hinge.
Discard any mussels that are already wide open and do not close when you tap them firmly on the counter, since those are dead and unsafe to eat.
Also discard any mussels with cracked or broken shells.
Heat the butter and olive oil in a large pot with a tight-fitting lid over medium heat until the butter melts.
Add the shallot and cook for 2 minutes, stirring often, until softened and translucent.
Add the garlic and red pepper flakes and cook for 30 seconds until fragrant, being careful not to let the garlic brown.
Pour in the white wine and bring it to a simmer, letting it bubble for 1 minute to cook off the raw alcohol smell.
Add all the cleaned mussels to the pot, cover with the lid, and increase the heat to medium-high.
Steam for 5 to 7 minutes, shaking the pot once or twice, until the mussel shells have opened wide.
Discard any mussels that remain tightly closed after 7 minutes of steaming, since those did not cook properly and should not be eaten.
Stir in the heavy cream and lemon juice and simmer uncovered for 1 minute to warm through.
Sprinkle in the parsley and toss gently to coat all the mussels in the broth.
Ladle the mussels and broth into bowls and serve immediately with slices of crusty baguette for dipping.