2) Place the remaining oil in a small saucepan, add the sliced garlic and cook until the sliced garlic is lightly golden brown. Remove the garlic slices with a slotted spoon to a plate lined with paper towels. Reserve the oil.
3) Increase the heat of the griddle to high. Remove the prawns from the marinade, season with salt and pepper and griddle until golden brown on each side, about 1 1/2 minutes per side. Remove from the skewers, transfer to a platter and drizzle with some of the reserved garlic oil and the garlic chips. Sprinkle with the remaining thyme and garnish with oregano leaves.