Preheat the oven to 180°C. Grease a muffin tin with butter.
Whisk the eggs in a bowl. Roughly chop the crayfish tails, add these to the eggs.
Add the Parmesan, lemon zest, your chosen vegetable, basil and a pinch of cayenne (if liked). Season with salt and pepper.
Gently combine, then spoon the mixture into the muffin tin. You should get about 6 muffins.
Bake in the oven for 20 minutes until golden, then let them cool in the tin for a couple minutes.
Transfer them to a plate and serve warm, or let them cool and cover/chill until needed.