Start by parboiling the potatoes so they grill quickly with the filet. Place the potatoes in a pot and fill them with cold water. Bring the mixture to a boil, then boil for 10 to 12 minutes.
Preheat your grill to high. It should be between 500 and 600 degrees F.
While the grill is heating, cut your filet into chunks. I like to use the baby potatoes so my filet chunks can be roughly the same size. I then also cut my peppers and onions into the same size chunks.
Skewer the steak, potatoes and veggies. I personally like to do 2 to 3 pieces of filet, 2 potatoes and lots of veggies on each skewer. You can make them however you’d like!
Spray the skewers with olive oil spray and sprinkle them with salt and pepper. Place them on the grill and grill on each side for 2 to 3 minutes, for a total of about 8 minutes. Remove the skewers and let them cool for a few minutes, then serve immediately with the rosemary chimichurri.