Meanwhile, in a food processor, process the bread to form coarse crumbs. In a medium skillet, heat 3 tablespoons of the olive oil. Add the garlic clove and cook over moderately low heat until golden, about 5 minutes. Discard the garlic clove. Stir in the anchovies and capers and cook, breaking up the anchovies, until the capers are crisp, about 1 minute. Add the red pepper and cook for 30 seconds. Stir in the bread crumbs and cook, stirring a few times, until golden and crisp, about 4 minutes. Transfer the bread crumbs to a plate and let cool. Stir in the walnuts.