Preheat your oven to 375°F (190°C) and lay out four slices of whole-grain bread on a baking sheet. Bake for 5-7 minutes, or until lightly toasted and crispy.

In a large frying pan or skillet, cook the four slices of bacon over medium heat until crispy. Flip halfway through cooking to ensure even browning.

Meanwhile, cook the turkey breast in a separate pan with a bit of oil over medium-high heat. Season with salt, pepper, and Dijon mustard. Cook for about 5-7 minutes per side, or until cooked through.

While the turkey is cooking, prepare the vegetables by slicing the lettuce, tomatoes, and avocado. Set aside.

Once the turkey is cooked, let it rest for a few minutes before slicing it thinly against the grain.

Assemble the sandwiches by spreading mayonnaise or Greek yogurt on each toasted bread slice, followed by a slice of turkey, a few slices of bacon, a lettuce leaf, a tomato slice, an avocado slice, and finally, a slice of cheese (if using).

Cook the eggs in a separate pan with a bit of oil over medium heat until scrambled and cooked through.

Finally, top each sandwich with a fried egg and place under the broiler for a minute or two to melt the cheese and cook the egg.