Boil the rigatoni in heavily salted boiling water until the pasta is al-dente i.e. they are soft but not mushy and still have a bite to it. Pastas will be cooked again in pesto sauce, so if you overcook your pasta while boiling, they will break and become completely mushy while tossing with pesto.
Reserve about a cup of pasta water before draining the pasta. Then transfer the pasta to a colander and wash it in running water. Leave it on the kitchen counter to let all the excess water drain out.
Heat a large pan big enough to hold all the pasta. Add the extra virgin olive oil to it and let it warm up a little but do not heat it to a very high temperature.
Once the oil is warm, add the basil pesto. Saute the pesto in olive oil for a good 5 to 6 minutes until oil starts to release.
After about 6 minutes, pour a couple of tablespoons of the reserved pasta water to the pan; this will deglaze the plan.
Now add the drained rigatoni to the pan and carefully mix them using a spatula. Take time at this stage so that each rigatoni is coated with the pesto and take on the vibrant green color. Season with salt & pepper.
When the pastas are nicely coated with pesto, sprinkle the grated cheddar cheese. Lightly mix them in. Then cover the pan with a lid and leave it on lowest heat for about 6 to 8 minutes to allow all the cheese to melt.
After about 8 minutes, uncover the pan and check if all the cheese has melted.
Divide your pesto rigatoni into 4 or 5 individual serving plates; drizzle a little olive oil on top, garnish with fresh basil and serve! Enjoy!
Recipe by Flavor Quotient at http://www.flavorquotient.com/2023/09/pesto-rigatoni-meatless-pasta-recipe/