Cook pasta until al dente, according to package directions. Meanwhile in a large skillet, warm 1 Tbs of oil over medium high heat. Add onion and garlic and cook, stirring frequently until onion begins to brown, about 5 minutes. Add the remaining 1 Tbs of oil to skillet. Add broccoli, bell pepper, oregano, salt, red pepper flakes and black pepper. Stir fry until the vegetables are crisp-tender, about 5 minutes. Stir in the half and half and the parmesan until combined. Reduce heat to medium, bring to a simmer, and cook stirring constantly, until mixture thickens slightly, about 2 to 3 minutes. Remove from heat. Drain pasta and transfer it to a large serving bowl. Add broccoli sauce, toss to coat and serve.