2 ounces dried Spanish chorizo, casing removed, thinly sliced
2 tablespoons olive oil, plus more for drizzling
3 garlic cloves, crushed
1 teaspoon fennel seeds, crushed
1 pint cherry tomatoes, halves
¾ cup dry white wine
Freshly ground black pepper
4 pounds mussels, scrubbed, debearded
4 slices thick country-style bread, toasted
2 tablespoons chopped fresh tarragon or parsley
Heat chorizo and 2 Tbsp. oil in a large heavy pot over medium, stirring occasionally, until chorizo begins to brown and crisp, about 4 minutes. Add garlic and fennel seeds and cook, stirring, until fragrant, about 1 minute. Add tomatoes and wine and bring to a simmer; season with pepper. Cook until reduced by three-quarters, 6–8 minutes.
Add mussels. Cover and cook, stirring occasionally, until mussels open, 6–8 minutes. Discard any mussels that don’t open. Drizzle toast with oil. Serve mussels topped with tarragon with toast alongside.