Bring a large pot of salted water to a boil over high heat. Cook the pasta according to package instructions, until al dente.

Meanwhile, heat the olive oil in a large skillet and sauté the shallots, garlic and red pepper flakes until translucent, about 2 minutes. Add the sausage and cook, breaking it apart with a wooden spoon and stirring occasionally, until browned and cooked through, about 8-10 minutes.

Add the chopped kale and season with salt and pepper. Cook until wilted, 2-3 minutes. Then, add the heavy cream and lower the heat to a simmer. Simmer until thick and reduced slightly, about 5 minutes. Remove from heat and add the lemon juice and zest, and the parmesan, stirring to combine.

Drain the pasta, reserving a little big of cooking water (1/4 cup). Add the pasta and reserved cooking liquid to the sauce and toss until combined.

Serve immediately!