I like to use sirloin tips because they are sliced perfectly for fajitas. You can use whole steaks if you wish and you can slice it before or after cooking.
Drizzle the soy sauce over the steak.
Combine the seasonings in a bowl.
Sprinkle the seasonings on both sides of the steak. Place the steak in a Ziploc bag. Seal the bag, removing all air. Pat the outside of the bag to ensure added soy sauce saturates the meat.
Place in fridge to marinate for at least 2 hours, preferably overnight.
Once the steak has finished marinating, place a grill on medium-high heat. Allow the grill to heat for 4-5 minutes.
Add the steak and grill until preferred doneness. Use a meat thermometer and test the interior of the meat to determine when it has finished cooking. The USDA minimum is 145 degrees. Here is a listing of the barometer: rare: 120-130 degrees, medium rare: 130-135 degrees, medium, 135-145 degrees, medium well 145-155 degrees, and well done 155 degrees.
Season the veggies with garlic powder and place the vegetables in a grill basket and grill for 7-10 minutes until the veggies are soft and slightly charred.
Melt 1 tablespoon of grass-fed butter in the microwave for 30 seconds and stir. After the steak has reached the desired doneness, using a cooking brush, brush the butter onto both sides of the steak while it’s on the grill.
Remove the steak from the grill and allow it to cool for 10-15 minutes before serving.
Spoon the mixture into the center of a lettuce leaf. Serve!