Place a medium or large skillet over medium-high heat, then pour 1 & 1/2 tbsp of olive oil.
Once the oil is ready, add the potatoes and fry until they are cooked. Do this in batches if all the potatoes don't fit in the pan.
Set the cooked potatoes aside.
Add and heat the remaining olive oil, add the garlic and onion and cook until they turned soft.
Add tomatoes, mix, then add peperoncino, salt, and pepper.
Mix to combine, then add the chopped eggplant and bell peppers.
Use your hands to tear the basil leaves and add them with the rest of the vegetables.
Mix everything, cover with a lid, and cook for about 5 minutes.
Adjust the heat to medium-low and continue cooking until the vegetables are cooked, mixing occasionally.
Taste and adjust the seasoning.
Add the fried potatoes and mix to combine evenly.
Place the lid back, adjust the heat to medium and cook for about 2 minutes.
Turn the heat off and transfer potatoes and peppers into serving plates.
Serve, with fresh basil leaves, if preferred.