Place shrimp in a small bowl. Dust with cayenne, salt, pepper and thyme. Toss and let sit for 10-15 minutes.
Add pasta to boiling water, add salt. Cook to al dente.
Melt butter in large skillet with the olive oil over medium heat.
Saute onion until soft (3-4 minutes).
Add garlic. Stir for 30 seconds (do not let garlic burn).
Add tomato paste, heavy cream, Parmesan and a small pinch of sugar. Stir and cook until blended.
Add the shrimp and cook for 2 minutes.
Add the pasta and toss; add reserved pasta water if it seems too dry.
Allow the shrimp to finish cooking (1-2 minutes). Do not overcook.
Add the parsley and squeeze the lemon over.
Serve!
Nutrition Info Per Serving: Calories 751 Total Fat 27 g Cholesterol 195 mg Sodium 1043 mg Potassium 670 mg Total Carbohydrate 100 g Dietary Fiber 14 g Sugars 3 g Protein 31 g