Turn the oven broiler on high.
Peel the grapefruit and cut it into 1/2 inch slices. Cut off the bitter pith around the edge of each slice.
If you don't want to have to use a knife to eat them, cut the pieces into quarters from there.
Arrange slices on a foil-lined baking sheet.
Dab the top of each piece with a piece of paper towel to dry it off.
Spread a thin layer of brown sugar on each piece.
Broil for around 8 minutes or until the sugar is bubbling but not burned.
Meanwhile, add Greek yogurt and muesli to a bowl.
Once the grapefruit is done, add it to the bowl.
Add a bit of chopped fresh mint if desired.
Drizzle the whole thing with honey and eat immediately.