How to Make It
In a large skillet, heat the 2 tablespoons of olive oil until shimmering. Add the onion, bell peppers, serranos, anchovy paste and a generous pinch each of salt and pepper. Cook over high heat, stirring occasionally, until the vegetables start to soften and brown on the edges, about 4 minutes. Add the vinegar and cook over moderate heat, stirring occasionally, until the peppers are tender, 5 to 7 minutes. Stir in the oregano and season the peperonata with salt and pepper; keep warm.
Preheat a grill pan. Brush the bread slices on both sides with olive oil. Grill over moderately high heat, turning once, until nicely toasted, about 2 minutes. Transfer the grilled bread to a plate and rub with the garlic clove. Spoon the peperonata on top and serve warm.