Pre-heat your oven to 375 °F (190 °C) for about 10-15 minutes.
While the oven is preheating, cut the eggplants into small bitesize cubes and lay out flat on a baking sheet in one layer.
Season the eggplant generously with salt, pepper, and Italian seasoning. Drizzle some good quality olive oil and ensure the cubes are evenly coated.
Once the oven is pre-heated, place the baking sheet with the eggplant cubes in the middle rack and roast for about 20 minutes or until the cubes turn a light golden brown color.
After the eggplant cubes are well-roasted, remove from the oven and set aside to cool.
Bring water in a saucepan to a boil and add in the rigatoni. Cook according to the directions on the packet. (9-11 minutes should suffice)
While the pasta is cooking, finely chop some onion and mince the garlic cloves.
Heat up a shallow frying pan with some olive oil on a medium flame.
When the pan is hot, toss in your onions and sauté until translucent.
Add in the minced garlic and stir in for 15-20 seconds. Be careful as garlic burns quite easily.
Spoon in some dollops of pesto from your favorite brand and mix in on a lower flame to ensure nothing sticks to the pan or burns.
Check in on your pasta and if it is al dente, set aside some of the pasta water in a separate glass or bowl. Drain the rest of the water using a colander.
Ladle in the pasta water to the pesto mixture and stir until the sauce is smooth.
Add in as many eggplant cubes as you want. If you have any leftovers, transfer them to a container and store in the fridge for future use.
Combine the rigatoni with the pesto sauce until the pasta is even coated and take off the heat.
Serve with some freshly grated parmesan on top and enjoy!