Rinse the mussels thoroughly, removing the beards.
Discard any mussels with cracked shells or those not closing tightly when touched.
Heat olive oil in a large earthenware casserole dish or Dutch oven over medium heat.
Add onion and garlic, cooking until the onion is wilted and transparent, about 3 minutes.
Stir in the gluten-free flour and cook for an additional 1 minute.
Add the parsley, white wine, clam juice or water, salt, and pepper.
Reduce the heat to low, cover, and simmer for 15 minutes.
Increase the heat to medium, add the mussels, cover, and cook for 5 minutes.
Uncover and cook, removing the mussels as they open.
Return the opened mussels to the skillet.
Discard any unopened mussels.
Notes / Tips / Wine Advice:
Serve the Spanish style mussels in green herb sauce hot. Dip into the vibrant green sauce with your favorite gluten-free bread and relish the delightful combination of flavors. ¡Buen provecho!
Wine Pairing:
Pair this Spanish style mussels dish with a crisp and refreshing Albariño or a dry Spanish Verdejo. The bright acidity of these white wines complements the savory flavors of the mussels and enhances the herbal notes of the green sauce.