Preheat oven to 425 degrees.
Dump broccoli onto half of a large, rimmed sheet pan. Drizzle with oil toss to coat. Arrange in a single layer (still on one half of the pan) and season with salt, pepper, garlic powder, and sprinkle with parmesan cheese. Bake in preheated oven for 10 minutes.
While broccoli is cooking, prepare the shrimp. Toss shrimp with the melted butter and garlic.
Arrange shrimp, in a single layer, on the unused half of the sheet pan. Return to oven for 5-6 minutes until shrimp is pink.
Squeeze fresh lemon over the shrimp, garnish with chopped parsley if desired, and serve.
