Marinate the beef: 24 hours before you want to cook, mix the marinade ingredients and add the marinade to a sealable container or bag with the beef cubes. Make sure the beef is fully coated in the marinade. Marinate in the fridge or cooler for 24 hours.
Assemble the kabobs: Slide the marinated beef cubes onto kabob skewers, leaving a little space between each piece. If you're using bamboo skewers, make sure to soak them in water first or they'll burn.
Cut the peppers and onions into pieces and slide them onto kabobs skewers. Drizzle with a little olive oil and sprinkle with salt.
Grill the kabobs: Place the kabobs on a grill grate over the fire. You want to hear a sizzle when they hit the grill.
Cook for about 10-15 minutes, or until the beef is done and the veggies are softened. Flip the kabobs every few minutes while they're cooking so they cook evenly.
Once done, remove the kabobs from the heat and serve immediately. Enjoy!
