Make Sauce

1. Mix all ingredients together in a bowl
2. Set aside

Steam Mussels

1. Scrub mussels under cold water & de-beard them. Discard any mussels with open or broken shells
2. Heat olive oil on medium-high
3. Sauté garlic & shallots 1 minute
4. Add mussels, white wine, and thyme. Steam 1-2 minutes, or until shells just open
5. Remove from heat & strain off liquid
6. Remove mussels from their shells and set aside

Make Batter & Fry

1. Stir sourdough starter & soda water until consistency is a little thicker than heavy cream
2. Heat a deep heavy-bottomed pot of canola oil (or small fryer) to about 350°
3. Lightly coat the mussels in the flour, then dip in the batter
4. Place the mussels in the hot oil & fry until golden, about 1-2 minutes
5. Place fried mussels on a paper towel to drain
6. Season with salt immediately if desired
7. Serve with the horseradish dipping sauce
8. Garnish with parsley