Roast the walnuts on low flame till they slightly brown and start releasing some of its oil. Allow to cool.
Wash your greens i.e. Spinach and basil and add those along with rest of the ingredients (except Parmigiano Reggiano) to the blender.
Blend until smooth. You can blend it till the texture you like. Some like their pesto smooth and some like it coarse. I opted for smooth for this recipe.
Remove from the blender into a clean cup/bowl and add the Parmigiano Reggiano to it. Mix well.
If you don't plan to use the pesto within a day or two I would recommend freezing it. In which case you can skip adding cheese and instead add it when you want to use the pesto.
When ready to use, just thaw the pesto, add the cheese and use as required. I usually freeze my pesto in ice cube trays and once set transfer to freezer safe Ziploc bags or containers.
For the Pasta:
In a pan heat some oil and add the tomatoes and saute for about 2 mins on medium heat. Then give them a gentle toss and add oregano, salt and pepper, and cook till look soft and juicy and yet retain their shape somewhat. Keep aside. (This step is completely optional)
Add pasta to boiling water that is seasoned with salt and cook as per package instructions till Al dente (approximately 10 -15 mins) or until how soft you like your pasta.
Strain the liquid and transfer the pasta back to the pot. Add a tablespoon of butter and give it a good mix.
Now add the pesto, tomatoes, Italian seasoning, chilli flakes, dry parsley salt and pepper. Give it a good mix and finally add the Parmigiano Reggiano.
Mix until everything is well combined.
Spinach Basil Pesto Pasta is ready!! Serve with some side of Garlic Bread or on its own topped with some generous sprinkle of Parmigiano Reggiano.
Spinach tends to oxidize and change color as soon as it hits the pan of pasta so I would recommend mixing then pesto and pasta only before serving it to retain the color. The color change however doesn't alter the taste.
To make it even more wholesome you can add some veggies to this pasta. Just boil them with pasta or cook them in some butter, salt and pepper and add to the pasta.
Cook the pasta al dente, as it will continue to cook once it's drained and mixed with the pesto.