Preheat griddle on low to medium low.
While griddle is heating up, season the steaks liberally with salt and pepper.
When griddle is hot (about 400-425 degrees F), add about 1-2 tablespoons of oil to the cooking surface and begin cooking the steaks. When steaks are about halfway done, flip to the second side and continue to cook until rare to medium rare. *The steak will go back on the griddle again later when it's mixed with the other fried rice ingredients, so you don't want to fully cook it now.
Transfer steaks to a cutting board and allow them to rest for several minutes before cutting into bite-sized pieces. Set cut steak to the side for later.
While steak is resting, add about 1-2 tablespoons of oil to the griddle and spread it around with your spatula. Add the cut mushrooms and vegetables to the griddle to cook in separate piles. Spread the mushrooms out in a thin even layer as they're cooking so they don't become soggy. Saute mushrooms and other vegetables separately, stirring occasionally.
When mushrooms are almost done, add minced garlic, Worcestershire sauce, 2 tablespoons butter, and bourbon (if using). Mix together and sauté for about 2 minutes, stirring frequently.
Add the cooked onions and asparagus to the mushrooms, sauté together for about 1-2 minutes, and move the vegetables to the side of the griddle to make room for the rice.
Add about 2 tablespoons of butter to the clean griddle surface. Add the cooked and cooled rice to the butter and mix together. Allow the rice to warm up and cook, stirring occasionally. Continue to stir the mushrooms and vegetables on the side of the griddle occasionally as the rice is cooking.
When the rice is almost done, add the cut steak to the griddle surface. Add the steak to the cooked mushrooms and vegetables and sauté together briefly. Then, add the fried rice to the meat and vegetables. Saute all ingredients together on the griddle for about 2-3 minutes. Then, turn the griddle off and move the fried rice to the side of the griddle while you make the yum yum sauce.
To make the yum yum sauce, add all sauce ingredients to a medium bowl and mix well.
Serve the steak and mushroom fried rice with the yum yum sauce and fresh sliced green onions for garnish. Enjoy!