Preheat oven to 180 C / 350 F. Line a baking tray with baking paper.
Cut the croissants horizontally into halves. Set aside.
Combine together melted butter, garlic and chopped parsley in a small bowl. Season with salt.
Place the croissants, cut sides down, on the baking tray. Brush croissant halves with garlic butter. Bake for about 4-6 minutes or until golden.
Make scrambled eggs:
Lightly whisk the eggs with milk. Season with salt.
Heat a small frying pan over medium heat-high heat.
Add butter. When hot, pour in egg mixture and let it sit for 15 seconds. Stir with a spoon, lifting and folding it over from the bottom of the pan. Repeat the process until the eggs are soft but slightly runny. Remove from heat.
Cook bacon:
Heat oil in the frying pan over medium heat. Add bacon strips. Cook, flipping and turning, for about 2-3 minutes or until browned evenly. Slice and set aside.
Make croissanwich:
Spread the croissant halves with mayonnaise. Place one bottom croissant half on a flat surface. Spread with mayonnaise. Top with lettuce, tomatoes, bacon and scrambled eggs and cheese slices. Place the top half of croissant over the cheese slices. Repeat with the remaining croissants and sandwich filling. Serve immediately.