Such an amazing pasta dish! I have been searching & testing for years to replicate what I taste in NYC restaurants and am in love with sausage and kale in pasta. More typically I see it with orecchiette and a more savory, lean sauce but this version goes above and beyond while remaining slightly healthy and not using a lot of cream.
Cook your pasta to al dente as directed by the packaging. Strain the pasta into a strainer reserving 1 cup of pasta water for later. Run cold water over the noodles until they are cold to the touch to stop the pasta from cooking further.
Top and tale your fennel and onion and dice each. In a stainless steel 6QT rondeau, add in your 3tbsp of olive oil and turn the heat to medium-high. When the pan and oil are warm, add in your fennel and onion and cook until translucent, fragrant, and very soft - about 8-10min. Add in your Italian sausage and be sure to break it up into small pieces as it cooks. Be sure to cook the sausage all the way through.
When the sausage is cooked, reduce the heat to medium and add in your garlic first. Cook until the garlic begins to become fragrant and then add in your tomato paste and tomato sauce. The tomato sauce & tomato paste should thicken quickly and you should start to smell cooking tomatoes - you want this! We want as much flavor as possible and when the tomato smells like its being cooked its removing excess water from the sauce. At this point, when everything in your pan is reduced down, add in your cup of white wine and stir to gently incorporate.
When the wine is done sizzling, turn the heat to low (or off entirely) and add in your cream. Stir the cream in to fully incorporate and then finish by stirring in your chili pepper flakes. Add black pepper & salt to taste. Add your pasta back in and stir to combine. Finish with torn basil & fresh ground parmesan cheese to taste.