Pat the shrimp dry and coat them evenly with the flour. Set aside.
In a large skillet over medium heat, melt the butter. Cook the bell pepper for 2 - 3 minutes, until it begins to soften.
Add the coated shrimp, garlic, and some salt and pepper to the pan and cook while stirring occasionally until the shrimp is cooked (and pink) all the way through and browned on the outside, 4 - 5 minutes.
Add the broth, lemon juice, heavy cream, and Parmesan to the pan and cook while scraping the brown bits off the bottom of the pan until the sauce thickens, another 3 - 5 minutes.
Pour over pasta and garnish with more Parmesan cheese and sliced green onions (if desired) and serve warm.