I love this recipe. It's one of my go-to's right now! I couldn't find nduja here in Japan so I just used whatever chili paste I have in the fridge. The first time, I used gochujang and it was sweet and spicy! The other time I used harissa and it was savory and herby! I'm not sure which one I liked more but both were delicious and worked so well in the recipe. I don't mind the amount of chili paste in this recipe since I love spicy food, definitely my type!
Also, if possible make sure to use freshy grated parmesan. Using the instant ones makes the sauce clumpy, at least in my experience.
