Preheat the oven to 180°C.
Cut the bagels in half (horizontally). Using a knife or cookie cutter, make the holes a little bit bigger.
Lightly grease the cut side of the bagels with butter or margarine.
Whisk the eggs in a small bowl. Finely grate the garlic and courgette, then add these to the egg.
Season with salt and pepper then add the parmesan, if used. Mix well.
Move the bagel nests onto a greased or lined baking tray, then spoon the egg mixture in the holes. Bake for 10-15 minutes in the middle of the oven. (You might need to cover it with foil, if the edges are getting too brown.)
Serve warm with a crunchy salad.