Place oil and potatoes in a large, deep non-stick skillet with a tight fitting lid on high heat; season with garlic powder, salt and pepper.

When the skillet gets hot and starts to sizzle, reduce heat to low and cook with a tight lid on for about 20-25 minutes, shaking the pan occasionally to prevent the potatoes from burning. Remove from heat and let them sit 5 minutes without removing the lid, then set the potatoes aside on a dish.

Add the sausage to the skillet and saute on medium-low and cook, stirring occasionally until browned but not quite cooked through, about 10 minutes.

Season chopped vegetables with salt and pepper. Add onions, peppers, garlic and rosemary to the skillet and mix.

Continue cooking, stirring occasionally, until onions and peppers become slightly browned. Add zucchini and cook an additional 5 minutes, mixing as it cooks until cooked through. Return the potatoes back to the skillet and mix well. Adjust salt and pepper as needed; cover and cook 5 more minutes.