Heat half the olive oil in a pan. When hot, add the mushrooms making sure not to crowd the pan. Fry until golden edges. Don't season your mushrooms. Trust me! Set aside.
In the same pan, add remaining olive oil. Add in the thinly sliced garlic, fresh cracked pepper and chilli flakes and let them bloom in the hot oil. Throw in the leeks and fennel, season with salt and fry until golden and caramelised. Move them around regularly to get even colour and avoid any burning.
Add the white wine to deglaze the pan and let it reduce to less than half.
Cook the pasta as per pack instructions in salted boiling water until al dente. Save a cup of the pasta water and drain.
Add the cooked pasta, mushrooms, pecorino and lemon zest and toss together, add in spoonfuls of pasta water until you have a lush sauce that clings to the pasta. Adjust seasoning.
Garnish with fresh parsley and more cheese should you so choose. Reward yourself with a glass of wine to enjoy with your pasta!