Heat the olive oil in a large skillet over medium heat. Add the sausage to the hot pan and break it into crumbles with a spatula. Add the crushed fennel seed and crushed red pepper flakes. Cook, stirring occasionally, for 5 minutes.
Add the minced garlic to the pan and cook, stirring constantly, for 1 minute.
Add the chicken broth, then simmer for 10 minutes. Taste the sauce and season with sea salt and freshly cracked pepper, to taste.
Meanwhile, cook the gnocchi in a large pot of well-salted water per instructions. Drain, then carefully spoon into the skillet with the sausage.
Add the spinach and cook, stirring often, for 1-2 minutes.
Pour into a serving bowl and top with freshly grated Parmesan, to taste.