Hard boil eggs. Once cooled, split in half. Discard yolk from 3 eggs; chop remaining eggs and yolks and add to a bowl.

Add chopped avocado, yogurt, lemon juice, chopped green onion, salt, pepper, and mustard; mash together and blend well.

Spread mixture onto bread slices and add fresh spinach, making 4 sandwiches. Serve with cubed mango on the side.