Add the rigatoni to boiling water and cook for 10 to 15 minutes until tender. Otherwise, follow the cooking instructions given on the packet.
Drain the rigatoni once al dente and rinse under cold running water to cool them to handle. Filter off the cold water and set them aside for a few minutes to cool well at room temperature.
In the interim, place the cast iron grilled pan over medium heat of your stove and add in the red capsicum with the skin side up. Grill the red capsicum for approximately 5 to 10 minutes or until slightly blackened. Remove the pan from heat and put them in a plastic bag. Put the bag aside so it can cool down.
Set the same cast iron grill pan over a medium-high heat and add in eggplant and the thick onion slices. Grill both of the ingredient for at least two minutes or until lightly charred, turning them over to cook them equally.
Add the button mushrooms, cherry tomatoes and the thickly sliced zucchini into the grill and cook for 2 to 3 more minutes. Remove the mixture from heat and place them in a large serving bowl.
Now, pick a sharp knife and gently cut the eggplant slices into 2 cm strips. Peel the grilled capsicum and cut into 2 cm strips. Add these two ingredients to the serving bowl and mix the pre-cooked pasta. Add in the rocket and gently toss the ingredients with a fork.
It is the time to prepare the dressing for the salad. Take a small bowl and pour in lemon juice, balsamic vinegar, and olive oil. Top the liquor-mixture with basil, capers, garlic and pepper to taste.
Give a slight stir to the dressing and gently pour it over the salad in the bowl.
Toss slightly to coat the ingredients sprinkle in the shaved Parmesan cheese.
Place the Rustic Grilled Vegetable and Rigatoni Salad in refrigerator for some time to chill and then serve immediately.