Prepare pasta according to package directions. Drain. Set aside.
In a medium bowl, add 1 tablespoon olive oil, oregano, salt and pepper. Mix well.
Add thawed shrimp. Toss to mix and cover.
Place a medium skillet over medium low heat.
Add shrimp mixture to skillet. Heat until just warmed through.
Remove shrimp from skillet to a large bowl. Do not clean skillet.
Add 1 tablespoon butter and olive oil to skillet. Allow butter to melt and get hot.
Add onion, red pepper flakes and thyme. Cook until onion is clear and soft, about 5 minutes.
Add garlic and tomato. Sauté about 2 minutes.
Add 1/2 cup broth. Allow to simmer until liquid evaporates, approximately 3 - 5 minutes.
Transfer this mixture to the shrimp bowl. Do not clean skillet.
Toss shrimp to combine. Set aside and keep warm.
Using the same skillet, add remaining 3 tablespoons of butter. Increase heat to medium and allow butter to melt. Do not burn.
Add flour. Whisk until blended.
Stir in cream, remaining broth and nutmeg. Increase heat to high and continue to stir.
Once sauce is simmering, reduce heat to low. Continue to simmer until sauce thickens, about 10 minutes.
Taste. Add salt and pepper, to taste.
Remove from heat. Toss with cooked pasta.
Place pasta on serving plates.
Top with shrimp and sprinkle with Parmesan cheese.