Preheat the grill on a medium setting.
Spray both sides of the sweet potato slice with low-calorie cooking spray and season well with salt and black pepper. Place on the grill pan rack and place under the preheated grill. Grill for 4-5 minutes on each side, or until soft inside and browning in places. Set aside and keep warm.
Spray a small frying pan with low-calorie cooking spray and place over a medium heat. Add the mushrooms and fry for 1 minute until softening.
Add the bacon and tomatoes to the frying pan and fry for 1 minute on each side, or until the bacon is cooked, the tomatoes have softened and the mushrooms are a little golden around the edges. Set aside and keep warm while you make the scrambled eggs.
In a small bowl, mix the beaten eggs with the water and season with salt and black pepper. Spray a small saucepan with low-calorie cooking spray and place over a medium heat. Add the egg mixture and cook gently for about 2-3 minutes, stirring, until lightly scrambled.
Place the toasted sweet potato slice on a plate and top with the slice of bacon. Add the scrambled egg, mushrooms and tomatoes and serve at once.