For caramelised garlic, preheat oven to 180C. Melt butter in a heavy-based oven-proof saucepan until golden, add garlic, stir to combine, then scatter with sugar and stir for 3 minutes or until garlic is golden. Add stock, cover and roast in the oven for 5 minutes.
Increase oven temperature to 200C. In a large cast-iron frying pan, melt butter, add dory, caramelised garlic cloves and black pepper and cook over high heat for 3 minutes or until browned. Turn and add fish stock, then bring to the boil, cover, transfer to oven and roast for 6 minutes. Turn fish and roast for a further 6 minutes.
To serve, place dory onto a plate, spoon over juices and garlic and scatter with parsley.