Add all the ingredients in the jar of a food processor and pulse to blend everything.
Keep in mind to not make a paste of the ingredients.
In between blending, keep scraping the sides of the blender using a spatula.
Add some more olive oil if required while blending.
It is best to use pesto freshly made but you can store it in an airtight container for up to 2 days.
Notes
Use freshest of basil and good cheese and olive oil to make the pesto. Since it requires only a handful of ingredients, it's very important to use the best.Do not make pesto in a blender or a mixie. It will become paste like. The correct texture of pesto is slightly coarse. You can use your food processor to make it. In fact in olden days, people used to make it in a mortar and pestle or chop it using their knife until all the ingredients came together and then lastly added olive oil to the finely minced ingredients.If Parmesan Cheese is not available, you can just skip it but do not add any other cheese.You can experiment with various greens to make the pesto. Although Basil is traditionally used, arugula, kale, carrot greens etc are great choices too.You can also play around with the nuts of your choice. Try adding almonds, pistachios, pinenuts instead of walnuts. Traditionally inenut were used to make pesto, but after experimenting with various nuts, I have realised that they give their own delicious flavour to the pesto.