Start by heating a cast iron pan to medium-high heat. I usually put my cast iron right on my grill and preheat it with the grill to 400-500℉. Add olive oil to the pan, then add peppers, onions, and garlic. Season with salt and pepper and stir. Close the grill to bring the temperature back up.
Prep the sausage by adding a little olive oil to coat them, so that they don't stick to the grill and pop. Once your grill reaches 400℉, place the sausage on the grill. At this time stir the peppers and onions. Once you start to see some charring on the onions, place a piece of aluminum foil over the cast iron. It doesn't have to be tightly wrapped, it will help keep some moisture in to soften the vegetables.
After 5 minutes, flip the sausage over to the other side for another 4-5 minutes. Continue to stir the peppers. If your sausage is getting too charred, lower the heat. Remove the sausage from the grill once it reaches 160℉. Rest the sausage on the cutting board for 10 minutes before cutting.
Cut the sausage and add it to the peppers and onions along with the basil. Stir in and remove from the grill. Allow the mixture to sit for 10 minutes. Serve on a sandwich or with your favorite rice!
Notes
Coat the sausage in a tiny bit of olive oil before putting them on the grill.
Try to keep the grill around 400℉ to make sure the casings don't start popping, like this one below. This sausage below popped open because the heat was too high.