Step 3
Meanwhile, heat the remaining 1 tablespoon oil in a large skillet over medium-low heat. Add anchovies and cook, stirring occasionally, until they have melted into the oil, 3 to 5 minutes. Add walnuts and cook, stirring occasionally, until lightly toasted, 4 to 6 minutes. Remove from heat. Stir in mustard, capers and vinegar.