Preheat oven to 450ºF and prepare a sheet pan lined with a sheet of parchment paper
Trim off the ends of the eggplant and cut into cubes. Add the cubes to a bowl and drizzle with enough olive oil to coat. Add a pinch of salt and toss immediately to avoid discoloration.
Pour out onto the sheet pan and spread out.
Roast for 20-minutes, toss once and cook for another 10 minutes or so until uniformly crisp all over.
Remove to let cool.
Prepare the other ingredients:
Cut the prosciutto into roughly 1-inch matchsticks.
Peel the potatoes and cut up into roughly 1-inch cubes. Place in a bowl and cover with cold water.
Trim the zucchini and cut into half-moon slices about 1/2-inch thick.
Bring a pot of water to boil and prepare an ice bath. Using a sharp knife, make a small X-shaped cut on the bottom of each tomato. Add the tomatoes to the boiling water for 1 minute to loosen the skin. Remove with a slotted spoon and place in the ice bath. When the tomatoes are cool, peel off the skin. Then rough-chop the tomatoes and set aside in a bowl.
Thinly slice the red onion. Peel the garlic clove, smash with the side of a knife and add to the onions.
Prepare the dish:
Using a large sauté pan, place over medium-low heat and add 1 tbsp of olive oil.
When the oil is hot, add the prosciutto. Slowly brown the prosciutto, stirring occasionally, to render out the fat and crisp. Remove the pan and set aside, leaving the accumulated oils.
Add the onions and garlic to the pan. Stir until lightly browned.
Raise the heat to medium-high. Drain the potatoes, giving them a good shake and then add to the pan. Depending on your type of pan, you may need add more olive oil. Stirring occasionally. gently fry the potatoes in the oil until they are lightly browned all over – about 10 minutes.
Add the zucchini with a pinch of salt and cook with the potatoes for about 10 minutes – stirring occasionally.
Add the tomatoes and mix into the pan ingredients. Cover and cook for another 10 minutes until the vegetables are cooked but not mushy.
Finally add the pre-cooked eggplant and prosciutto and stir into the vegetables. Taste to adjust the salt and pepper to your liking.
Scatter torn basil leaves over the vegetables and serve with a little grated Parmesan cheese.