Pre-heat the oven to 220° C.
Brush the monkfish tail with half of the olive oil then season generously. Arrange on a lined roasting tray and roast for 25-35 minutes until the flesh is opaque and springy to the touch.
Mix the peppers in a large mixing bowl with the remaining olive oil. Season to taste and spoon onto a rectangular serving plate. Remove the monkfish when ready and sit on top of the peppers. Garnish with sprigs of thyme before serving.