Dr. Pepper Marinade

In a large measuring cup, whisk together the Dr. Pepper, Worcestershire Sauce, balsamic vinegar, and 1 teaspoon of the kosher salt. 

Transfer the steak pieces to a zipper-lock bag and pour 1 cup of the marinade in the bag. Squeeze out the air and zip to close. Refrigerate the bag of steak for 4-12 hours. Cover and refrigerate the remaining marinade until ready to use. 

Grilling Prep

About 30 minutes before you’re ready to grill, pull the steak from the fridge and let it sit at room temperature, to shake off the chill from the fridge. Get your grill going to 450-500 degrees F, with a hot side and a cool side.

Thread the steak pieces onto flat skewers, about 5 piece of steak per skewer. Be sure not to jam the steak pieces tightly together on the skewer. Discard the bag of marinade. 

Pat the kebabs dry with paper towels and sprinkle with pepper and 2 teaspoons of kosher salt. 

Place the kebabs on oiled grates and grill uncovered, turning every 1-2 minutes until the steak is charred on all sides; move them to the cool side and repeat until all the kebabs have some char and are medium-rare. About 4-6 minutes. 

Remove the kebabs from the grill, transfer to a sheet pan and tent with foil. Let the steak rest for 15 minutes.

Dr. Pepper Sauce

While the steak is resting, we can prepare the Dr. Pepper Sauce. Pour the reserved cup or so of Dr. Pepper mixture into a saucepan and bring to a boil over medium-high heat. Reduce the heat to a simmer. Stirring occasionally, let the mixture simmer until it is reduced to about ¼ cup (about 10 minutes.) Stir in the butter and keep simmering over medium heat until the sauce is slightly thickened to lightly coat the back of a spoon, about 2 minutes. 

Drizzle a little sauce over the kebabs and serve the remaining Dr. Pepper Sauce alongside the kebabs.