Lightly oil the grill pan with some of the butter. Turn the heat on until butter begins to foam.
Rinse the leek and chop the top and bottom off. Slice it in half lengthwise so you have 2 long slices.
Place on the grill pan and leave to cook on one side. Lightly press the leek to make sure it cooks through. Do the same for the other side until it is noticeably softened.
Make the garlic butter. Mince the garlic and add to the granules. Add the desired amount of salt and using a spoon press the garlic into the salt. Add the butter and mix together and season with the pepper.
Brush the garlic butter onto the inside of the leeks (so the side which would have been sliced into). Repeat on the other half.
