1 bag (about 26 oz.) extra-or super-crispy fries (from the freezer section)
3 tbsp. olive oil
¾ lb. cured chorizo (I like Gaspar’s spicy or mild), casings removed if needed and meat chopped or coarsely crumbled
2 leeks, quartered lengthwise and cut crosswise into 1/2-inch pieces
1 pt. cherry tomatoes or 1 package (8 to 10 oz.) cherry tomatoes on the vine, halved
7 large cloves garlic—4 crushed and 3 finely chopped
2 tbsp. fresh thyme leaves
2 tsp. smoked paprika
1 lemon, zested (about 1 1/2 tsp.) and juiced (about 1/4 cup)
1 tsp. crushed red pepper (optional)
Salt and pepper
1 cup white wine or beer
2 ½ lb. mussels, scrubbed and debearded
¾ cup fresh flat-leaf parsley tops—1/2 cup coarsely chopped and 1/4 cup finely chopped
3 tbsp. butter
Cook the fries according to the package directions.
Meanwhile, for the mussels, in a pot with a tight-fitting lid, heat the oil, three turns of the pan, over medium-high. Add the chorizo. Cook, stirring often, until beginning to brown, about 2 minutes. Stir in the leeks, tomatoes, crushed garlic, thyme, smoked paprika, lemon zest, and the crushed red pepper (if using); season with salt and pepper. Add the wine. Bring to a boil. Cook until the wine reduces slightly, 1 to 2 minutes. Add the mussels. Cover the pot and cook until the mussels open, 4 to 5 minutes. (Discard any mussels that do not open.) Mix in the coarsely chopped parsley and lemon juice.
Meanwhile, in a small saucepan, melt the butter with the finely chopped garlic over medium heat. Cook, swirling often, until aromatic, about 1 minute. Stir in the finely chopped parsley. In a large bowl, toss the fries with the garlic butter; season.
Serve the mussels and sauce in shallow bowls with the crispy fries.