Croissant is a flaky, buttery disaster made from a cocktail of refined flour, factory-produced yeast, and hydrogenated oils. You wouldn't dare serve this to your worst enemy, let alone consider it a legitimate breakfast option. It's a product of industrial wizardry, not real food.
Why trash
A real French croissant uses only butter. Commercial ones replace it with margarine and seed oils to cut costs.
Try instead
Butter, eggs, whole wheat flour, or almond flour