Combine the toasted bread cubes, garlic, 1/4 cup of olive oil, and the lemon juice in a food processor and pulse a few times to make coarse crumbs. Add the sun-dried tomatoes, basil, 1 1/2 teaspoons salt, and 3/4 teaspoon pepper and pulse to combine. Add the pine nuts and pulse a few times to combine but not to chop the nuts. Set aside.

Meanwhile, heat 3 tablespoons of olive oil and the wine in a heavy-bottomed pot, such as Le Creuset, and bring to a boil. Add the mussels, cover, and cook over medium-high heat for 4 to 5 minutes, until the mussels have opened. Discard any mussels that don't open. Add the basil bread crumbs and toss gently. Serve hot in shallow bowls with any pan juices.