Place large eggs in a medium pot and cover with cold water. Heat over high until boiling, cover, turn off heat, and let sit for 10-12 minutes. Cool under cold running water.

Cut ripe avocados in half and remove the pit. Scoop out the flesh and mash it until smooth yet slightly chunky.

Peel and chop the cooled eggs into small pieces. Fold them into the mashed avocado with mayonnaise or Greek yogurt, Dijon mustard, salt, pepper, and herbs.

Slice fresh croissants in half horizontally and lay the halves cut-side up on a clean cutting board.

Spoon the avocado egg salad onto the bottom half of each croissant, then place the top half over the salad. Press down gently to secure.

Serve sandwiches fresh or, if wrapping for later, keep them tightly wrapped to maintain freshness.