Preheat oven to 400°F (200°C). Prepare a baking sheet with cooking spray.

Arrange tomato halves onto prepared baking sheet. Drizzle olive oil over the tomatoes; season with salt and pepper.

Roast tomatoes in preheated oven until edges are crisp, about 35 minutes. Let cool and cut into small chunks.

Cook angel hair pasta in boiling salted water, stirring occasionally, until al dente, about 4-5 minutes; drain and transfer to a large bowl.

Melt butter in a skillet over low heat. Cook and stir onion, garlic, and half the basil in the butter until onion is translucent, about 5 minutes.

Add shrimp, tomato chunks, mushrooms, and garlic powder to the skillet. Cook and stir over medium-low heat until shrimp is pink and cooked through, about 6 minutes.