1. In a large skillet, melt half the butter, then add mushrooms and season with salt. Stir often, until browned, then remove from heat and allow to cool.
2. In a bowl, whisk together egg, flour and sesame seeds. Then fold in the cooked mushrooms.
3. Place the skillet back over medium-high heat and melt the remaining butter. When the butter has melted, add the mushroom mixture to the pan. Cook until the bottom is firm and browned, about 5 minutes, then flip and cook for an additional 2 to 3 minutes or until the mixture is set.
4. Cut into wedges and serve topped with scallions, cilantro, mayo, Maggi and hot sauce.