In a small bowl, stir together mayonnaise and pesto. Set aside.
In a small non-stick skillet set over medium heat, add a drizzle of oil. Saute the slice of onion until slightly softened and caramelized on both sides, being careful to keep the whole slice intact. Remove the onion slice and set aside.
In the same skillet, add the turkey sausage patties and Canadian bacon, heating until warmed through. Remove from pan.
To the same skillet, add another drizzle of oil and crack the egg into the skillet. Cook the egg to your liking and top with a slice of cheese.
Meanwhile, toast the croissant and then spread a thin layer of the pesto mayo on each half of the croissant. On the bottom half, layer the sausage, onion, Canadian bacon, egg with cheese, and bacon. Top with fresh basil and the other half of the croissant. Serve and enjoy!