Cook the whole wheat fusilli according to the package directions.
While the pasta is cooking, heat the olive oil in a large pan over medium heat. Add the diced onion and cook until translucent, about 5 minutes.
Add the sliced leek and minced garlic to the pan and cook for another 3-4 minutes until the leek is soft.
Add the sliced mushrooms and cook until they have released their water and started to brown, about 8-10 minutes.
Stir in the sweet and smoked paprika powders and cook for one minute until fragrant.
Pour in the vegetable broth, scraping the bottom of the pan to release any browned bits. Bring to a simmer and let it cook for 5 minutes.
Reduce the heat to low and stir in the oat whipping cream. Season with salt and pepper to taste. Let it simmer gently for another 2-3 minutes, but do not bring to a boil.
Drain the cooked fusilli and add it to the pan with the paprikash sauce. Toss everything together until the pasta is well coated.