Set the oven to 400 degrees. Lightly grease a 10 inch baking dish.
Bring a large pot of water to a boil. Add the salt and angel hair stir with tongs cook until the pasta is al dente about 4 minutes. (Check pasta package for specific time) Drain the pasta and transfer it to a bowl. Toss it with a drizzle of oil season with salt and pepper. Use tongs to transfer to the baking dish in one fairly even layer.
Use the pasta bowl to toss together the mushrooms, onion, oil oregano, salt and pepper. Spoon the mixture over the pasta and drizzle with heavy cream.
Transfer to the hot oven and roast the vegetables for 35 to 40 minutes or until they are tender and the pasta is crisp at the edges. Serve immediately.