How to Make It
Arrange the sardines in a shallow baking dish. Pour 1/2 cup of the olive oil over the sardines and top with two-thirds of the chopped garlic. Season with salt and black pepper. Let the sardines stand at room temperature for 30 minutes.
Meanwhile, in a mini food processor, combine the piquillo peppers with the sherry vinegar, cayenne pepper and the remaining chopped garlic; puree until smooth. Add the remaining 1/4 cup of olive oil and puree until incorporated. Season the piquillo pepper sauce with salt and pepper.
Light a grill or preheat a grill pan. Oil the grill and grill the sardines, flipping them once, until they are lightly charred and cooked through, about 4 minutes. Transfer the sardines to a large platter and serve with the piquillo pepper sauce and grilled peasant bread.