In a large skillet, heat the olive oil and butter over medium-high heat. Add the potatoes and season with salt and pepper.
Cook until browned on one side, 6 to 7 minutes. Turn the potatoes over and cook for another 4 to 5 minutes, or until golden brown and tender. Remove the potatoes from the skillet with a slotted spoon onto a plate.
If you are using beef kielbasa, you may not need to add additional olive oil, but with turkey you may need to. Add the kielbasa and cook for 2 to 3 minutes on each side, until lightly browned. Remove kielbasa to a separate plate and pat with a paper towel to absorb some of the grease. Return to skillet.
Add the onions and pepper to the skillet and sauté until the onions are soft and translucent and the peppers and tender. Then add the garlic and let cook another minute. Season with salt and pepper.
Stir the potatoes back in and let heat back up for another couple of minutes.
Taste to see if you need to add more salt and pepper then serve.