Cook the penne according to package directions and drain.
Meanwhile, heat 1 TBS of the olive oil in a large skillet over medium-high heat. Add the prosciutto and cook for about 2 minutes or until crisp. Remove the prosciutto from the skillet and set aside.
Add the remaining 1 TBS of olive oil to the skillet, chopped onion, garlic and red pepper flakes and stir. Cook for about 3 minutes or until the onion is tender.
Add the zucchini to the skillet and cook for 2 minutes; then, add the tomatoes. Season with salt and pepper and cook for 2 additional minutes. Remove from heat.
Stir in the penne, balsamic vinegar, prosciutto, half of the parmesan cheese and the parsley.
Divide into 4 bowls and garnish with the leftover Parmesan cheese.