Whisk broth, Parmesan, cream, and ½ teaspoon pepper together in bowl; set aside. Cook pancetta and butter in 12-inch nonstick skillet over medium-high heat until pancetta is beginning to brown, 2 to 4 minutes. Add broccoli and remaining ¼ teaspoon pepper and cook, stirring occasionally, until broccoli is bright green, about 3 minutes.
Add gnocchi and cook until beginning to brown, about 3 minutes. Stir in garlic and cook until fragrant, about 1 minute. Add broth mixture and bring to simmer. Cook, stirring occasionally, until sauce is slightly thickened and broccoli and gnocchi are tender, about 3 minutes. Stir in lemon juice and season with salt and pepper to taste. Serve.
