1. Prepare the maple mustard sauce by whisking together mayonnaise, mustard, and maple syrup in a small bowl until smooth. Set aside.
2. Preheat the oven to 420°F and arrange the bacon slices on a baking sheet lined with parchment paper. Cook for 10-15 minutes until crisp.
3. Shape maple sausage into thin rectangle patties to fit inside the croissants. Cook sausage in a skillet over medium heat for about 7-8 minutes on each side until fully cooked.
4. In a mixing bowl, beat together the eggs, milk, and a pinch of salt and pepper. Scramble the eggs in a non-stick skillet over medium-high heat until fluffy and fully cooked.
5. Slice the croissants open and lightly toast them under a broiler to make them warm and flaky.
6. Spread a generous layer of the prepared maple mustard sauce on each half of the toasted croissants.
7. Assemble the sandwich by layering scrambled eggs on the bottom half of the croissant, followed by sausage, crispy bacon, and a sprinkle of shredded Colby Jack cheese.
8. Add a touch of minced chives as a garnish for freshness.
9. Place the top half of the croissant onto the assembled layers to finish the sandwich.
10. Serve immediately and enjoy the rich, savory, and slightly sweet flavors of the Killer Maple Mustard Croissant Breakfast Sandwiches.