Roughly chop the eggs into smaller pieces and transfer to a mixing bowl. Add in the onions, capsicums, chilis, coriander leaves
Now add the mustard sauce, mayonnaise, salt and pepper and give everything a through mix. Check for seasoning and adjust if needed and keep the stuffing aside
Slit the croissants from the sides and make a hollow for stuffing. Stuff the spinach leaves in it and about 3-4 tablespoons of the stuffing, evenly in the croissant
You could serve these croissant egg sandwiches right away or warm them up for about 30 seconds on a skillet/microwave oven and then serve. Enjoy!