Heat grill to the highest setting. Whisk the eggs in a bowl and season.
Melt the butter in a sauté pan over a medium heat. Add the eggs and cook for 2 mins, then spoon the crab and asparagus into the middle. Sprinkle over the chilli and nestle the spinach into the egg. Grill in the pan for 2-3 mins or until the spinach has wilted and the omelette has puffed up.