Start by adding 2 tbsp of extra-virgin olive oil and the chopped mushrooms into a deep frying pan on a medium heat. Season with salt and pepper and fry for 5 minutes, stirring frequently.
Then, on a low heat, add the finely chopped onion to fry for a further 5-8 minutes. Slowly the excess moisture will evaporate so that the mushrooms and onion can start to take on some colour and caramelise. Now add the tomato puree and garlic.
Continue to stir and gently fry the tomatoey/mushroom mix until fully incorporately.
Meanwhile, add the rigatoni into salted boiling water, with the timer set to the packet instruction time, minus 2 minutes.
Reserve the pasta water while draining the rigatoni and transfer the undercooked pasta into the deep frying pan. Add around 3 ladles of pasta water. Stir to coat the rigatoni in the sauce and continue to cook until the pasta water has emulsified to form a glossy, delicious tomato sauce.
Now add the panko breadcrumbs into a separate frying pan with the remaining oil, chopped basil and a pinch of flaky salt. Gently fry for a couple of minutes until golden brown.
Serve the mushroom ragu with the salty, toasted basil breadcrumbs and an additional sprinkle of basil.